1,151 research outputs found
Reconstructing Bohr's Reply to EPR in Algebraic Quantum Theory
Halvorson and Clifton have given a mathematical reconstruction of Bohr's
reply to Einstein, Podolsky and Rosen (EPR), and argued that this reply is
dictated by the two requirements of classicality and objectivity for the
description of experimental data, by proving consistency between their
objectivity requirement and a contextualized version of the EPR reality
criterion which had been introduced by Howard in his earlier analysis of Bohr's
reply. In the present paper, we generalize the above consistency theorem, with
a rather elementary proof, to a general formulation of EPR states applicable to
both non-relativistic quantum mechanics and algebraic quantum field theory; and
we clarify the elements of reality in EPR states in terms of Bohr's
requirements of classicality and objectivity, in a general formulation of
algebraic quantum theory.Comment: 13 pages, Late
Natural resource inventories and management applications in the Great Basin
ERTS-1 resolution capabilities and repetitive coverage have allowed the acquisition of several statewide inventories of natural resource features not previously completed or that could not be completed in any other way. Familiarity with landform, tone, pattern and other converging factors, along with multidate imagery, has been required. Nevada's vegetation has been mapped from ERTS-1. Dynamic characteristics of the landscape have been studied. Sequential ERTS-1 imagery has proved its usefulness for mapping vegetation, following vegetation phenology changes, monitoring changes in lakes and reservoirs (including water quality), determining changes in surface mining use, making fire fuel estimates and determining potential hazard, mapping the distribution of rain and snow events, making range readiness determinations, monitoring marshland management practices and other uses. Feasibility has been determined, but details of incorporating the data in management systems awaits further research and development. The need is to accurately define the steps necessary to extract required or usable information from ERTS imagery and fit it into on-going management programs
Non-singular inflationary universe from polymer matter
We consider a polymer quantization of a free massless scalar field in a
homogeneous and isotropic cosmological spacetime. This quantization method
assumes that field translations are fundamentally discrete, and is related to
but distinct from that used in loop quantum gravity. The semi-classical
Friedman equation yields a universe that is non-singular and non-bouncing,
without quantum gravity. The model has an early de Sitter-like inflationary
phase with sufficient expansion to resolve the horizon and entropy problems,
and a built in mechanism for a graceful exit from inflation.Comment: 4 pages, 1 figure; v2 clarifications added, reference update
Least-cost number, size, and location of turkey-processing plants in Minnesota, Iowa, and Wisconsin
In the last few years, various reports have dealt with costs of operation of turkey-processing plants. Through these reports and through their own experiences, processing plant managers are well aware of the existence of economies of large-scale operation and the reduction in costs possible from operating at or near capacity. Although the significance of economies of large-scale operation for the individual plant manager is well understood, the significance of these economies for an entire marketing system or for an entire turkey-production region has not been systematically investigated.https://lib.dr.iastate.edu/specialreports/1060/thumbnail.jp
Semiclassical states for quantum cosmology
In a metric variable based Hamiltonian quantization, we give a prescription
for constructing semiclassical matter-geometry states for homogeneous and
isotropic cosmological models. These "collective" states arise as infinite
linear combinations of fundamental excitations in an unconventional "polymer"
quantization. They satisfy a number of properties characteristic of
semiclassicality, such as peaking on classical phase space configurations. We
describe how these states can be used to determine quantum corrections to the
classical evolution equations, and to compute the initial state of the universe
by a backward time evolution.Comment: 13 page
UMP clinched 9 medals at BioMalaysia 2011
Universiti Malaysia Pahang (UMP) continued to record successful achievements by garnering a gold medal, a silver medal and seven bronze medals at the BioMalaysia 2011 and Pacific RIM Summit on Industry and BioEnergy 2011 in Kuala Lumpur recently. The event was officially opened by Prime Minister Dato’ Sri Mohd Najib Tun Razak at Kuala Lumpur Convention Centre on November 21, 2011
Quantity and Quality Limit Detritivore Growth: Mechanisms Revealed by Ecological Stoichiometry and Co-Limitation Theory
Resource quantity and quality are fundamental bottom-up constraints on consumers. Best understood in autotroph-based systems, co-occurrence of these constraints may be common but remains poorly studied in detrital-based systems. Here, we used a laboratory growth experiment to test limitation of the detritivorous caddisfly larvae Pycnopsyche lepida across a concurrent gradient of oak litter quantity (food supply) and quality (phosphorus : carbon [P:C ratios]). Growth increased simultaneously with quantity and quality, indicating co-limitation across the resource gradients. We merged approaches of ecological stoichiometry and co-limitation theory, showing how co-limitation reflected shifts in C and P acquisition throughout homeostatic regulation. Increased growth was best explained by elevated consumption rates and improved P assimilation, which both increased with elevated quantity and quality. Notably, C assimilation efficiencies remained unchanged and achieved maximum 18% at low quantity despite pronounced C limitation. Detrital C recalcitrance and substantive post-assimilatory C losses probably set a minimum quantity threshold to achieve positive C balance. Above this threshold, greater quality enhanced larval growth probably by improving P assimilation toward P-intensive growth. We suggest this interplay of C and P acquisition contributes to detritivore co-limitation, highlighting quantity and quality as potential simultaneous bottom-up controls in detrital-based ecosystems, including under anthropogenic change like nutrient enrichment
On the nature of continuous physical quantities in classical and quantum mechanics
Within the traditional Hilbert space formalism of quantum mechanics, it is
not possible to describe a particle as possessing, simultaneously, a sharp
position value and a sharp momentum value. Is it possible, though, to describe
a particle as possessing just a sharp position value (or just a sharp momentum
value)? Some, such as Teller (Journal of Philosophy, 1979), have thought that
the answer to this question is No -- that the status of individual continuous
quantities is very different in quantum mechanics than in classical mechanics.
On the contrary, I shall show that the same subtle issues arise with respect to
continuous quantities in classical and quantum mechanics; and that it is, after
all, possible to describe a particle as possessing a sharp position value
without altering the standard formalism of quantum mechanics.Comment: 26 pages, LaTe
Evaluating Recruitment of American Eel, Anguilla rostrata, to the Potomac River (Spring 2006)
Fisheries management techniques are not often applied to American eels because basic biological information is not well known. Unknown biological parameters such as variation in growth rates and length at age have complicated stock assessment and management efforts. Though American eel are not usually considered a sport fish, their ubiquity and readiness to take a bait leads them to be caught by recreational fishermen (Collette and Klein-MacPhee, 2002). Young American eel are also used as a baitfish in coastal areas (Jenkins and 4 Burkhead, 1993.) Absence of basic population dynamics data has hampered attempts at evaluation of regional exploitation rates (Social Research for Sustainable Fisheries, 2002). Additionally, relatively few studies have addressed the recruitment of glass eels to Atlantic coast estuaries from the Sargasso Sea spawning grounds. The Atlantic States Marine Fisheries Commission (ASMFC) adopted the Interstate Fishery Management Plan (FMP) for the American eel in November 1999. The FMP focuses on increasing the states’ efforts to collect data on American eel and the fishery it supports through both fishery dependent and fishery independent studies. To this end, member jurisdictions (including the PRFC) agreed to implement an annual abundance survey for young of year (YOY) American eels. The survey is intended to “…characterize trends in annual recruitment of young of year eels over time [to produce a] qualitative appraisal of the annual recruitment of American eel to the U.S. Atlantic coast (ASMFC, 1999). These surveys began as pilot surveys in 2000 with full implementation by the 2001 season. Survey results will provide critical data on eel coastal recruitment success and further understanding of American eel population dynamics
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