Thesis (Ph. D.)--University of Chicago, Dept. of Anthropology, August 2002. / Includes bibliographical references. Also availablle on the Internet.

Thesis (Ph. D.)--University of Notre Dame, 2005. / Thesis directed by Daniel J. Myers for the Department of Sociology. "July 2005." Includes bibliographical references (leaves 242-274).

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 143-149).

No description available.

Η παρούσα εργασία αναφέρεται στην ανάπτυξη ενός ολοκληρωματικού μοντέλου 2ης τάξης για επίπεδες και κυκλικές, τυρβώδεις ανωστικές φλέβες σε περιβάλλοντα όπου επικρατεί στρωματοποίηση πυκνότητας και αποτελεί επέκταση μελέτης του Αναπληρωτή Καθηγητή του Πανεπιστημίου Πατρών Παναγιώτη Γιαννόπουλου η οποία έχει δημοσιευτεί υπό τον τίτλο “ An improved integral model for plane and round turbulent buoyant jets” στο περιοδικό J. Fluid Mech. το 2006, όπου μελετάται και αναπτύσσεται ένα παρόμοιο μοντέλο σε μη στρωματοποιημένο περιβάλλον. Αρχικά οι μερικές διαφορικές εξισώσεις του όγκου, της ορμής και της διατήρησης του ιχνηθέτη ολοκληρώνονται στην διατομή της ανωστικής φλέβας, παίρνοντας δεδομένο πως ισχύει η αρχή της αυτό-ομοιότητας. Το κλείσιμο της τύρβης επιτυγχάνεται με την υπόθεση ενός σταθερού ρυθμού εξάπλωσης της ανωστικής φλέβας μέχρι το σημείο που αυτό παγιδεύεται εξαιτίας της στρωματοποίησης. Οι κανονικές διαφορικές εξισώσεις που προκύπτουν από αυτή την ολοκλήρωση σχηματίζουν ένα σύστημα εξισώσεων το οποίο λύνεται με την βοήθεια ενός αλγορίθμου Runge-Kutta 4ης τάξης που διαμορφώσαμε κατάλληλα. Έπειτα το μοντέλο επικυρώνεται με την σύγκριση των αποτελεσμάτων αυτής της αριθμητικής διαδικασίας με αποτελέσματα απο Yannopoulos (2006) και εξάγονται συμπεράσματα και παρατηρήσεις για την επίδραση της στρωματοποίησης στην διάδοση της φλέβας, επιπλέον επιχειρείται μια προσπάθεια ανάπτυξης ενός συμπληρωματικού μοντέλου ρευστομηχανικής ανάλυσης των φαινομένων που εξελίσσονται εντός της παγιδευμένης περιοχής. Σκοπός συνεπώς αυτής της εργασίας είναι η ανάπτυξη ενός αξιόπιστου ερευνητικού εργαλείου που θα μπορέσει να προβλέπει κατανομές ταχυτήτων, συγκεντρώσεων αλλά και γεωμετρικά και άλλα σημαντικά μεγέθη σε τυρβώδεις ανωστικές φλέβες που εμφανίζονται σε περιβάλλοντα όπου η στρωματοποίηση παίζει σημαντικό ρόλο. / The specific study refers to the development of a second order integral model for plane and round, turbulent, buoyant jets in stratified environments and is considered as an extension to the primary study of Pr. Yannopoulos, of the university of Patras, which was published under the title "An improved integral model for plane and round turbulent buoyant jets” in 2006 at J. Fluid Mech where a similar model is being studied in a uniform environment. Originally the partial differential equations of volume, momentum and conservation of tracer are integrated in the cross section of the buoyant jet with the help of the self similarity assumption. The closure of the turbulence is succeeded with the use of the spreading concept up to the point where the jet gets trapped. The ordinary differential equations that result from this procedure produce a set of equations which gets solved by a 4th order Runge-Kutta algorithm which was configured properly. After that the model gets validated via the comparison of its results with the findings of Yannopoulos for the same phenomenon in a uniform environment so that we can make observations and reach to conclusions considering the effect of stratification for the spreading of the jet. Moreover the development of a complementary model is attempted in order to provide a fluid dynamic analysis for the phenomena that take place inside the trapped area. Therefore the purpose of the specific study is the development of a reliable research tool that can predict the distributions of velocity and concentration as well as geometric and some other important quantities that play a significant role in these kind of jets.

Based on available studies on business and management fields of study as upwardly-mobile university field of study choices as a basis, this study seeks to test this hypothesis of upward mobility. In doing so, it endeavours to identify correlations between field of study choice and educational background and between field of study choice and gender. The base data is taken from a survey of all domestic first-time students at Austrian universities in the 2011/12 winter semester (N=27,575). This data was subjected to a correspondence analysis, which allowed us to visualise and interpret the relations between the positions of these fields of study in the university space. The results indicate a clearly structured (stratified) university space. Our supplementary regression analysis shows that the upwardly-mobile higher education choice hypothesis can be confirmed for the fields of study studied. Our analyses also confirm the feminisation hypothesis for the business and management fields of study studied: women significantly more frequently select fields of study which lead to a career in a pedagogic (business education), social (social economy) or language (international business and management) context. In the group of fields of study explored, business education fields of study had both the highest share of first-time students and the highest level of feminisation. In contrast, economics fields of study, which was included in the analysis in addition to the business studies and management fields of study, have a significantly higher share of male students and the lowest share of higher education climbers. (authors' abstract)

The decision of whether to enter higher education or not is strongly structured by social background, i.e. parents’ social class. This paper examines if and to what extent enrolment in tertiary education also is related to social capital, and furthermore, if social capital can account for differences in social background. Two aspects of social capital are examined: extended network resources, operationalized as family acquaintances holding different occupations, and peer influences, assessed as the number of friends already engaged in higher educational studies. The sample consists of two subsequent surveys of Swedish adolescents, divided in three stratums based on parents’ country of birth: Iran, former Yugoslavia and Sweden. The findings suggest that resources and returns of extended social networks enhance the probability of enrolment to university studies. The results concerning peer influences seem to indicate an impact on the probability of university admission, however, there might be causal and analytical problems of measurement involved.

Made available in DSpace on 2015-04-17T14:55:27Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1578704 bytes, checksum: 75147d7247375585e2e4f31faeb6f2a3 (MD5) Previous issue date: 2013-02-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The capture of birds in the canopy is not a common methodology, mainly for logistical reasons, even though several authors have proposed techniques. There is also the concern that aspects that depend on handling birds are becoming relegated before the current state of forests. This study aimed to develop a methodology from existing techniques and present its performance in comparisons between morning and afternoon, edge and interior, and three different canopy heights; as well as describe the community of canopy birds captured in three Atlantic Forest fragments of Paraíba, Brazil, from richness, abundance, diversity, trophic structure, similarity and biological and morphometric data. The method developed here was based primarily on those suggested by Greenlaws and Swinebroad (1967) and Munn (1991). All materials, adaptations, step by step assembly and use are presented. We captured 171 individuals of 28 species in 12 families. The afternoon (χ ² = 8.895, df = 1, p = 0.003), the edge (χ ² = 7.164, df = 1, p = 0.009) and heights between 15 and 25 m (χ ² = 6.00, df = 2 p = 0.049) were the best situations encountered. Methodologies for working with bird can be linked to the peak of activity and place of sampling for greater success. The highest catch rate during the afternoon may reflect the increased activity of birds before the night rest and climatic factors. The larger number of captures in the forest edge can be explained by the presence of species and the quantity of resources influenced by the adjacent matrix and external environmental factors. The capture rate in median heights may have been greater for having covered both species in the higher as the lower regions of the canopy. Pipridae and Thraupidae were the most representative families captured. Among the recorded species, 60.71% are considered canopy specific, 28.57% are medium stratum specifc and 10.71% are understory and ground vegetation specific. Frugivores, insectivores and omnivores are 28.57% of species each, while nectarivores accounted are 14.28%. The areas were considered similar (C33 = 0.62) and showed similar diversity. There were two reproductive and a moulting peaks, and the morphological data from 28 species of captured birds are presented. The dominance of canopy species occurred as expected. The equal dominance of frugivorous, insectivores and omnivores is unusual as the canopy is generally dominated by frugivorous; as well as the low number of representatives of the family Tyrannidae, which is considered the most representative in studies of terrestrial birds. The results of diversity and similarity of areas occurred as expected, given the proximity and historic of the areas. The reproductive peaks are close to those reported in the literature as being from September to January in Brazil. As also commonly reported, the molting period does not coincide with the breeding, probably due to the energy expenditure involved. Morphometric and biomass data presented here are pioneers due to lack of information of birds in this stratum. Aspects to be highlighted in this adaptation are the low cost and ease of finding and handling materials, and the low disturbance of the sampling region. The situations encountered here are suggested in studies performed in fragments with similar dynamics. Further studies are recommended on capturing birds in the canopy to a better knowledge of the avifauna in this forest stratum. / A captura de aves no dossel não é uma metodologia frequente, principalmente por motivos logísticos, mesmo que diversos autores tenham proposto técnicas. Existe ainda a preocupação de que aspectos que dependem do manuseio das aves passem despercebidos diante do preocupante estado atual das florestas. Este trabalho objetivou desenvolver uma metodologia a partir de técnicas já existentes e apresentar seu desempenho em comparações entre manhã e tarde, borda e interior, e três diferentes alturas de dossel; assim como descrever aves capturadas no dossel de três fragmentos de Mata Atlântica da Paraíba, Brasil, a partir da riqueza, abundância, diversidade, estrutura trófica, similaridade e dados biológicos e morfométricos. A metodologia desenvolvida aqui foi baseada principalmente naquelas sugeridas por Greenlaw e Swinebroad (1967) e Munn (1991). Todos os materiais, adaptações, passo a passo da montagem e utilização são apresentados. Foram capturados 171 indivíduos de 28 espécies, em 12 famílias. O período da tarde (χ² = 8,895; g.l = 1; p = 0,003), a borda (χ² = 7,164; g.l = 1; p = 0,009) e alturas entre 15 e 25 m (χ² = 6,00; g.l = 2; p = 0,049) foram as melhores situações encontradas. Metodologias para o trabalho com a avifauna podem ser atreladas ao pico de atividade e local de amostragem para um maior sucesso. A maior taxa de captura durante a tarde pode ser reflexo do aumento da atividade das aves antes do descanso noturno e de fatores climáticos. A presença de uma maior quantidade de indivíduos capturados na borda florestal pode ser explicada pela presença de espécies generalistas e pela maior quantidade de recursos por influência da matriz adjacente e fatores climáticos externos. A taxa de captura em alturas medianas pode ter sido maior por ter abrangido tanto espécies presentes de regiões mais altas quanto de regiões mais baixas do dossel. Pipridae e Thraupidae foram as famílias mais representativas. Dentre as espécies registradas, 60,71% são consideradas de dossel, 28,57% de estrato médio e 10,71% de sub-bosque e vegetação rasteira. Frugívoros, insetívoros e onívoros representaram 28,57% das espécies cada, enquanto que nectarívoros representaram 14,28%. As áreas foram consideradas 14 similares (C33 = 0,62) e apresentaram diversidade parecida. Foram observados dois picos reprodutivos; e um pico de muda de penas. Os dados morfológicos das 28 espécies de aves capturadas são apresentados. A dominância de espécies de dossel ocorreu conforme esperado. A dominância de forma igual de frugívoros, insetívoros e onívoros é um aspecto incomum, já que o dossel é geralmente dominado por frugívoros; assim como o baixo número de representantes da família Tyrannidae, a qual é tida como mais representativa em estudos de aves terrestres. Os resultados de diversidade e similaridade das áreas ocorreram como esperado, diante da proximidade e histórico das áreas. Os picos reprodutivos encontrados estão próximos ao relatado na literatura, como sendo de setembro a janeiro no Brasil. Também como frequente, o período de muda não coincide com a reprodução, provavelmente em função do gasto energético envolvido. Os dados morfométricos e de biomassa apresentados são pioneiros devido a escassez de informações de aves nesse estrato. Aspectos a serem ressaltados nesta adaptação são a facilidade de encontrar e manusear os materiais, custos acessíveis e menor perturbação da região de amostragem. As situações encontradas aqui são sugeridas em trabalhos realizados em fragmentos com dinâmica semelhante. São recomendados mais estudos de captura de aves no dossel para um melhor conhecimento da avifauna nesse estrato florestal.

Electric hot water tanks play a pivotal role as demand response assets within the UK's energy system by storing heat when energy is inexpensive and delivering domestic hot water when it is required. This role will become increasingly important if non-dispatchable renewable energy sources are to play a bigger part in the energy mix. Historically, the design standards relating to hot water tanks have focused primarily on minimising heat losses. However, in addition to preserving energy, a hot water tank should preserve the availability of heat above a useful temperature for as long as possible to avoid energy usage during peak times when it is costly or carbon intensive. To do this, thermal stratification within hot water tanks must be promoted. Unfortunately, thermal stratification leads to conditions that are conducive to bacterial growth due to the hospitable temperatures that arise during operation. For this reason, question marks have arisen over the extent to which more flexible control strategies, designed to allow for increasing penetrations of intermittent renewable energy sources, might lead to the growth of pathogenic bacteria within hot water tanks. The objective of the work discussed in this thesis was to understand the extent to which there is a conflict between thermal stratification and bacterial growth in practice, whether this conflict can be resolved and the potential implications for electric hot water tanks operating on a time of use tariff. A small field study demonstrated that there is prolific bacterial growth within conventional electric cylinders and that this can be attributed to thermal stratification with a confidence of (P<0.01). Fitting a de-stratification pump, to enhance sanitary performance, resulted in a 19% decrease in the recovery of useable hot water above 43°C. Given that the tanks tested during the field study were made of copper, the consequences of alternative material choices on thermal performance were explored. It was found that the rate of useable hot water loss, due to de-stratification associated with thermal diffusion across the thermocline, could be reduced by a factor of 2.7 by making the tank liner wall from stainless steel instead of copper. Further numerical work indicated that this improvement in stratifying performance was most significant for small tanks with high aspect ratios. In addition to de-stratification that arises due to vertical conduction, de-stratification due to inlet mixing was reduced by up to 30% by installing a spiral diffuser into the base of a test cylinder. In addition, by lowering the immersion heating element to ensure there is sufficient heat transfer to the base of the cylinder, sterilising temperatures could be attained throughout the stored volume of water in the tank during heating. This showed that the conflict between thermal and sanitary performance within electric tanks could potentially be resolved. A bespoke tank, made from stainless steel and fitted with a diffuser, was built and subjected to typical draw cycles that reflect real world operation. These tests showed that more useable hot water could be delivered in comparison to a commercial off the shelf copper tank and consequently the utilisation of the Economy 7 time of use tariff would be enhanced.

Cette thèse est consacrée à l'étude des fibres de l'application moment du système de Mumford (pair ou impair) d'ordre g>0. Ces fibres sont paramétrées par des courbes hyperelliptiques de genre g. Comme l'a démontré Mumford, la fibre au-dessus d'une telle courbe lisse est la jacobienne de la courbe, moins son diviseur thêta. Nous décrivons les fibres au-dessus d'une courbe singulière, à la fois de manière algébrique et géométrique. Pour ce faire, nous utilisons de façon essentielle les g champs de vecteurs du système de Mumford, qui définissent une stratification de chaque fibre, où chaque strate est isomorphe à une strate particulière (dite maximale) d'une fibre d'un système de Mumford d'ordre inférieur. Sur cette strate, tous les champs de vecteurs du système de Mumford sont linéairement indépendants en tout point. Nous décrivons cette strate comme un ouvert de la jacobienne généralisée d'une courbe hyperelliptique singulière. Nous montrons également que sur la jacobienne généralisée, les champs de Mumford sont des champs invariants par translation. / This thesis is dedicated to the study and to the description of the fibres of the momentum map of the (even or odd) Mumford system of degree g>0. These fibres are parameterized by hyperelliptic curves. Mumford proved that each fiber over a smooth curve is isomorphic to the Jacobian of the curve, minus its theta divisor. We give a geometrical as well as an algebraic description of the fibers over any singular curve. The geometrical description uses in an essential way the g vector field of the Mumford system. They define a stratification of each fiber where each stratum is isomorphic to a particular stratum, called the maximal stratum, of a fiber of a Mumford system of degree at most g. The algebraic description uses the theory of subresultants, which is applied to the polynomials which parametrize the points of phase space. We show that every stratum is isomorphic with an affine part of the generalized Jacobian of a singular hyperelliptic curve. We also prove that the Mumford vector fields are translation invariant on these generalized Jacobians.