785 research outputs found
Charge and the topology of spacetime
A new class of electrically charged wormholes is described in which the outer 2-sphere is not spanned by a compact, co-orientable hypersurface, These wormholes can therefore display net electric charge from the source-free Maxwell equations. This extends the work of Sorkin on non-space-orientable manifolds, to spacetimes which do not admit a time orientation. The work is motivated by the suggestion that quantum theory can be explained by modelling elementary particles as regions of spacetime with non-trivial causal structure. The simplest example of an electrically charged spacetime carries a spherical symmetry
A prony algorithm for shallow water waveguide analysis
Submitted in partial fulfillment of the requirements for the degree of Ocean Engineer at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution August 1987Low frequency acoustic propagation in shallow water is examined from a normal
mode context. By modelling the far field pressure field as a modal sum, propagating mode
characteristics of wavenumber, initial phase, attennation and amplitude may be estimated
using a high resolution parameter modeling technique. The advantages of such an
algorithm are the resolution of closely spaced modes in a range independent environment
and the ability to analyze range dependent waveguides.
This thesis presents the application of a Prony algorithm to the shallow water
environment. The algorithm operates directly on the signal matrix. Synthetically
generated, range independent pressure fields are used to analyze the technique'S
performance and to observe its sensitivity to variations in model specifications. Noise is
added to determine the threshold of acceptable performance. As a consequence of field data
tests, further enhancements to the algorithm are suggested.
Range dependent performance is evaluated on a coastal wedge example and
geoacoustic parameter shift example
Unraveling the Complexity of Critical Consciousness, Political Efficacy, and Political Action Among Marginalized Adolescents
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141719/1/cdev12446.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141719/2/cdev12446_am.pd
The effects of computer inservice and training on the adoption of a computerized grading system
While technology has been entering the educational setting for many years, there are teachers who continue to be fearful about adopting computers and other technology into their classes. Whenever new technology is introduced, teachers have legitimate concerns: How does this affect my daily routine? Will this replace me as a teacher? How will I learn about the new device? Is it right for the student? (Poirot, 1992b). These concerns can be answered if the technological implementation is successful. Creating a setting that is conducive to initial teacher acceptance of the technology and an eventual adoption of the tool at a personal level is the key (Poirot, 1992b)
The Khwe of Namibia, foragers between game, tourism and politics
__Abstract__
In this paper we examine the plight of the Khwe Bushmen, a group of (former) hunter-gatherers in the
Bwabwata National Park in Northern Namibia. The Khwe have lived for a long time in the area of
Bwabwata, so are highly affected by the parkâs conservation activities that altered their environment
seriously. Although they were historically hardly involved in decision making on or the
implementation of such activities, this was supposed to change with the rise of Community-Based
Natural Resource Management (CBNRM) in the 1990s. Yet, many of its aims did not materialize and
the approval of the Kavango Zambezi Transfrontier Conservation Area (KAZA TFCA) in 2011 aimed
at increased conservation in the area. An important element in these plans is to boost âgreen economicâ
growth by increasing tourism, also involving the Khwe Bushmen.
As a theoretical starting point, we use Ingoldâs dwelling perspective, based on hunter-gatherer
ontologies, in which the world comes into being because an organism/person is continuously
interacting with his/her environment, through bodily activity. Dwelling is contrasted with building, in
which (wo)man constructs the world cognitively before (s)he can live in it. We apply a third notion,
namely lodging, to refer to a situation in which people live in an essentially foreign environment. We
argue that today many changes in the environment of the Khwe are triggered beyond their control,
instead of through their interaction with their environment. In this concept, the environment is
dominant and the people have no option but to adapt to changes in their environment outside their
control.
Using these three notions of dwelling, building and lodging we analyse various conservation
and tourism developments in the environment of the Khwe, historically as well as more recently. In so
doing, we show the transformation of the cultural understanding the people have of their environment,
of their interaction with it (and with the various actors and stakeholders) and with each other
Torsion cycles as non-local magnetic sources in non-orientable spaces
Non-orientable spaces can appear to carry net magnetic charge, even in the
absence of magnetic sources. It is shown that this effect can be understood as
a physical manifestation of the existence of torsion cycles of codimension one
in the homology of space.Comment: 17 pages, 4 figure
Application of the Instrumental Inequalities to a Mendelian Randomization Study With Multiple Proposed Instruments
BACKGROUND: Investigators often support the validity of Mendelian randomization (MR) studies, an instrumental variable approach proposing genetic variants as instruments, via. subject matter knowledge. However, the instrumental variable model implies certain inequalities, offering an empirical method of falsifying (but not verifying) the underlying assumptions. Although these inequalities are said to detect only extreme assumptio
The Role of International Administration [IA] in the Globally Engaged University
This paper describes best practice and effective techniques in international administration (IA) within the Globally Engaged University. The Globally Engaged University is one that continually promotes, communicates, initiates, controls, monitors, and evaluates international activity in at least one of its major academic units [5]. Emphasis is IA within engineering and technology higher education. Nonetheless, the description of best practice in IA is also applicable to various other academic disciplines at the Globally Engaged University. In describing best practice in IA, the paper adds the perspective of the authors' applied experience. The combined IA experience among the coauthors includes successful international programs in South and Southeast Asia, the European Union, and the USA. Three of the co-authors are senior administrators within one and the same university in the USA. Another co-author is a senior administrator at a university in Malaysia. Broadening the perspective yet further, another team member is an IA specialist at a Globally Engaged University in Poland. The authors compare and contrast techniques and organizational structure common to IA at three differing locations: USA, Malaysia, and Poland as a central member state of the European Union
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