1,513 research outputs found
Aspects of the internal physics of InGaAs/InAlAs quantum cascade lasers
We report on the results of our simulations of an InGaAs/InAlAs midinfrared quantum cascade laser (QCL) designed to operate in continuous wave mode at room temperature [Beck et al., Science 295, 301 (2002)]. Our physical model of the device consists of a self-consistent solution of the subband population rate equations and accounts for all electron-longitudinal-optical phonon and electron-electron scattering rates, as well as an evaluation of the temperature of the nonequilibrium electron distribution. We also consider the role of the doping density and its influence on the electron dynamics. We found that the temperature of the nonequilibrium electron distribution differed significantly from the lattice temperature and that this temperature increased with applied electric field and current density, with coupling constants somewhat larger than analogous GaAs based midinfrared QCLs. Our simulations also reveal physical processes of the device that are not apparent from the experimental measurements, such as the role of electron-electron scattering. © 2006 American Institute of Physic
Co-governance or meta-bureaucracy? Perspectives of local governance 'partnership' in England and Scotland
This article assesses the nature of partnerships through the research site of local governance in England and Scotland, engaging a range of debates and literature around governance and meta-governance. The research used secondary data of local authority partnership working in England and Scotland as well as primary qualitative data from participant observation and interviews with senior officials of local authorities and partner organisations. There is little to suggest that English and Scottish practices are significantly at variance and the article advances an argument of meta-bureaucracy to describe partnerships' activities: that is to say, partnerships do not represent a growth of autonomous networks and governance arrangements but rather an extension of bureaucratic controls. State actors remain pre-eminent within increasingly formalised systems of 'partnership'
Twisted trees and inconsistency of tree estimation when gaps are treated as missing data -- the impact of model mis-specification in distance corrections
Statistically consistent estimation of phylogenetic trees or gene trees is
possible if pairwise sequence dissimilarities can be converted to a set of
distances that are proportional to the true evolutionary distances. Susko et
al. (2004) reported some strikingly broad results about the forms of
inconsistency in tree estimation that can arise if corrected distances are not
proportional to the true distances. They showed that if the corrected distance
is a concave function of the true distance, then inconsistency due to long
branch attraction will occur. If these functions are convex, then two "long
branch repulsion" trees will be preferred over the true tree -- though these
two incorrect trees are expected to be tied as the preferred true. Here we
extend their results, and demonstrate the existence of a tree shape (which we
refer to as a "twisted Farris-zone" tree) for which a single incorrect tree
topology will be guaranteed to be preferred if the corrected distance function
is convex. We also report that the standard practice of treating gaps in
sequence alignments as missing data is sufficient to produce non-linear
corrected distance functions if the substitution process is not independent of
the insertion/deletion process. Taken together, these results imply
inconsistent tree inference under mild conditions. For example, if some
positions in a sequence are constrained to be free of substitutions and
insertion/deletion events while the remaining sites evolve with independent
substitutions and insertion/deletion events, then the distances obtained by
treating gaps as missing data can support an incorrect tree topology even given
an unlimited amount of data.Comment: 29 pages, 3 figure
Foodways and a Violent Landscape: A Comparative Study of Oneota and Langford Human-Animal-Environmental Relationships
ABSTRACT:
FOODWAYS AND A VIOLENT LANDSCAPE: A COMPARATIVE STUDY OF ONEOTA AND LANGFORD HUMAN-ANIMAL-ENVIRONMENTAL RELATIONSHIPS
by
Rachel C. McTavish
The University of Wisconsin-Milwaukee, 2019
Under the Supervision of Robert Jeske
The goal of this research is to investigate the nature of Upper Mississippian human-animal-environmental relationships (circa AD 1050-1450), to evaluate the role of resource management, the role of sustainability, and the multi-faceted nature of human-animal relationships, to understand how these choices are related to adaptations to structural violence. The research uses the Koshkonong Locality of southeastern Wisconsin and the Fox/Des Plaines Locality as case studies to compare divergent Upper Mississippian practices within the northern Prairie Peninsula.
This study uses zooarchaeological vertebrate and invertebrate data. Inclusive zooarchaeological datasets provided useful information about basic dietary trends, ecological management systems, environmental niche exploitation, and non-economic human-animal relationships.
The Oneota and Langford groups occupying the Lake Koshkonong and Fox/Des Plaines localities were likely responding to structural violence and the threat of potential physical violence within their daily resource choices. However, they show different cultural choices in the more nuanced manners in which they responded to systemic violence. These nuances can be connected to the divergent perspectives on placemaking and longevity on the landscape and the connections between choices in sustainability and management of local resources.
Overall, this dissertation research has called into question and provided a case for the re-evaluation of previous site typological assumptions and how groups settling within a “locality” interact in a socio-economic and political manner. While previous researchers have classified and analyzed the Robinson Reserve and Schmeling sites as villages, the inclusion of more data and a larger understanding with more village sites excavated in these localities allows for their re-interpretation as mortuary sites. In re-labeling the Robinson Reserve and Schmeling sites as having a mortuary function rather than a daily village life function, the demographic served in these specific locations on the landscape is shifted. This shift is necessary for the interpretation of the faunal assemblages, but more so it shifts the overarching ideas of what sites are located within these localities, what types of sites one can expect to find in future surveys and excavations. The intra-locality subsistence data and inter-cultural subsistence data indicates the value for a nuanced approach is necessary for testing how a group or groups’ daily choices are affected by the threat of systemic violence.
These two veins of research allows for future discussion of what is involved in Late Prehistoric groups’ decisions and concepts of placemaking- placemaking as marked by the surfaces used by the living, by the dead, and when those places are made and intertwined by both. Most importantly, the challenge to previous site typologies and the more nuanced examination of intra locality and inter-cultural subsistence data shifts the way in which we interpret the human-environmental relationship for groups in the region
City of West Palm Beach v. Board of Trustees of the Internal Improvement Trust Fund, Nos. 93,821, 1999 WL 731654 (Fla. Sept. 9, 1999)
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