4,362 research outputs found
Critical behavior of a bounded Kardar-Parisi-Zhang equation
A host of spatially extended systems, both in physics and in other
disciplines, are well described at a coarse-grained scale by a Langevin
equation with multiplicative-noise. Such systems may exhibit non-equilibrium
phase transitions, which can be classified into universality classes. Here we
study in detail one of such classes that can be mapped into a
Kardar-Parisi-Zhang (KPZ) interface equation with a positive (negative)
non-linearity in the presence of a bounding lower (upper) wall. The wall limits
the possible values taken by the height variable, introducing a lower (upper)
cut-off, and induce a phase transition between a pinned (active) and a depinned
(absorbing) phase. This transition is studied here using mean field and field
theoretical arguments, as well as from a numerical point of view. Its main
properties and critical features, as well as some challenging theoretical
difficulties, are reported. The differences with other multiplicative noise and
bounded-KPZ universality classes are stressed, and the effects caused by the
introduction of ``attractive'' walls, relevant in some physical contexts, are
also analyzed.Comment: Invited paper to a special issue of the Brazilian J. of Physics. 5
eps Figures. 9 pagres. Revtex
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
Grouper culture in floating net cages
The manual describes the culture of groupers (Epinephelus) in floating cages, providing a farming option for grouper growers and also a production alternative to the farmed species being done today, such as shrimp, milkfish and tilapia. The following aspects are covered: species identification for commercially cultured groupers; source of stock; net cage specifications; anchor; hides and shelters; nursery net cage operation; production cages; harvesting; post-harvest; profitability analysis of grouper cage culture; and, cost and return of growing grouper in cages
A Framework for the Design and Implementation of Learning Objects: a Competence-based Approach
This paper presents a framework for the design and implementation of learning objects using a competence-based approach. This framework is illustrated by the development of a standalone Windows application (Trilho GOA) whose primary purpose is to create standardized pedagogical contents trough the aggregation and standardization of instructional resources in several formats that can be used later on a Learning Management System (LMS) supporting SCORM 1.2. The paper contains a brief introduction to the developed software, its system architecture, main features and several pedagogical advantages for its users
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