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

A domain-analytic perspective on sexual health in LCSH and RVM

This paper analyses and compares the treatment of sexual health in Library of Congress Subject Headings (LCSH) and Répertoire de vedettes-matière de l’Université Laval (RVM) using three of Bowker and Star’s (1999) infrastructural inversion techniques: practical politics, convergence, and resistance. Our findings reveal that neither LCSH nor RVM offer a holistic representation of sexual health (practical politics), that LCSH’s topical representation of sexual health limits access to relevant material (convergence), and that the enhancement of LCSH through user-added content could improve but not replace these systems (resistance)

“WHAT WERE YOU THINKING?”: THE USE OF METACOGNITIVE STRATEGY DURING ENGAGEMENT WITH READING NARRATIVE AND INFORMATIONAL GENRES

This qualitative case study illustrates and compares the metacognitive strategies that a grade‐3 female student used while reading narrative and informational texts. Data were collected from interviews, observations, and videotaping of the participantʹs narrative and informational text oral reading sessions and examined using thematic analysis. Findings showed that she used markedly different metacognitive strategies for each genre, resulting in comprehension difficulties while reading the inform‐ ational text. This article suggests that for students to meet the challenges of inform‐ ational texts, they must be taught specific metacognitive strategies while working with explicit text patterns. Key words: metacognition, comprehension, text, stimulated recall, self‐regulation Cette étude de cas qualitative illustre et compare les stratégies métacognitives utilisées par une élève de 3e année en lisant des textes narratifs et informatifs. Les données, provenant d’entrevues, d’observations et de vidéos des séances de lecture à haute voix de ces textes par la participante, ont fait l’objet d’une analyse thématique. Les résultats indiquent que l’écolière avait recours à des stratégies métacognitives nettement différentes pour chaque genre de textes, ce qui entraînait des difficultés de compréhension pour les textes informatifs. Il semble donc que, pour que les élèves soient en mesure de saisir les textes informatifs, il faut leur enseigner des stratégies métacognitives particulières tout en tenant compte de la structure explicite du texte. Mots clés : enseignement de la lecture, métacognition, compréhension, texte, rappel stimulé, autocontrôle.