20 research outputs found
The agrarian question and violence in Colombia: conflict and development
This article examines connections between Colombia’s internal armed conflict and agrarian questions. It pays attention to the country’s specific historical trajectory of agrarian change, the violent expression of social tensions that this elicited, and the particular ways in which these dynamics were influenced by a changing global context.This analysis of the intimate ties between violent conflict and agrarian questions in Colombia, both in terms of their historical development and their contemporary manifestations, challenges popular notions of the relationship between armed conflict and development. In particular, the article contributes to a critique of the conventional version of the conflict–development nexus by illustrating ways in which the experience of capitalist development in Colombia has been violent and produced poverty
Tight-binding parameters from the full-potential linear muffin-tin orbital method: A feasibility study on NiAl
We have examined a method of direct extraction of accurate tight-binding
parameters from an ab-initio band-structure calculation. The linear muffin-tin
potential method, in its full-potential implementation, has been used to
provide the hamiltonian and overlap matrix elements in the momentum space.
These matrix elements are Fourier transformed to real space to produce the
tight-binding parameters. The feasibility of this method has been tested on the
intermetallic alloy NiAl, using spd orbitals for each atom. The parameters
generated for this alloy have been used as input to a real-space calculation of
the local density of states using the recursion method.Comment: 12 pages, RevTex, 5 figure
Proposal for an experimental test of the many-worlds interpretation of quantum mechanics
The many-worlds interpretation of quantum mechanics predicts the formation of
distinct parallel worlds as a result of a quantum mechanical measurement.
Communication among these parallel worlds would experimentally rule out
alternatives to this interpretation. A procedure for ``interworld'' exchange of
information and energy, using only state of the art quantum optical equipment,
is described. A single ion is isolated from its environment in an ion trap.
Then a quantum mechanical measurement with two discrete outcomes is performed
on another system, resulting in the formation of two parallel worlds. Depending
on the outcome of this measurement the ion is excited from only one of the
parallel worlds before the ion decoheres through its interaction with the
environment. A detection of this excitation in the other parallel world is
direct evidence for the many-worlds interpretation. This method could have
important practical applications in physics and beyond.Comment: 17 pages, standard LaTex, no pictures, comments welcome, revised
version corrects typing error in mixing tim
Philosophy Enters the Optics Laboratory: Bell's Theorem and its First Experimental Tests (1965-1982)
This paper deals with the ways that the issue of completing quantum mechanics
was brought into laboratories and became a topic in mainstream quantum optics.
It focuses on the period between 1965, when Bell published what now we call
Bell's theorem, and 1982, when Aspect published the results of his experiments.
I argue that what was considered good physics after Aspect's experiments was
once considered by many a philosophical matter instead of a scientific one, and
that the path from philosophy to physics required a change in the physics
community's attitude about the status of the foundations of quantum mechanics.Comment: 57 pages, accepted by Studies in History and Philosophy of Modern
Physic
O(N) methods in electronic structure calculations
Linear scaling methods, or O(N) methods, have computational and memory
requirements which scale linearly with the number of atoms in the system, N, in
contrast to standard approaches which scale with the cube of the number of
atoms. These methods, which rely on the short-ranged nature of electronic
structure, will allow accurate, ab initio simulations of systems of
unprecedented size. The theory behind the locality of electronic structure is
described and related to physical properties of systems to be modelled, along
with a survey of recent developments in real-space methods which are important
for efficient use of high performance computers. The linear scaling methods
proposed to date can be divided into seven different areas, and the
applicability, efficiency and advantages of the methods proposed in these areas
is then discussed. The applications of linear scaling methods, as well as the
implementations available as computer programs, are considered. Finally, the
prospects for and the challenges facing linear scaling methods are discussed.Comment: 85 pages, 15 figures, 488 references. Resubmitted to Rep. Prog. Phys
(small changes
Rhinitis in the geriatric population
The current geriatric population in the United States accounts for approximately 12% of the total population and is projected to reach nearly 20% (71.5 million people) by 2030[1]. With this expansion of the number of older adults, physicians will face the common complaint of rhinitis with increasing frequency. Nasal symptoms pose a significant burden on the health of older people and require attention to improve quality of life. Several mechanisms likely underlie the pathogenesis of rhinitis in these patients, including inflammatory conditions and the influence of aging on nasal physiology, with the potential for interaction between the two. Various treatments have been proposed to manage this condition; however, more work is needed to enhance our understanding of the pathophysiology of the various forms of geriatric rhinitis and to develop more effective therapies for this important patient population
The half life of carbon fourteen and a comparison of gas phase counter methods /
Work performed at the Brookhaven National Laboratory, University of Minnesota, Massachusetts Institute of Technology."AECU-780"Includes bibliographical references (p. 2).Mode of access: Internet