Novel gain enhancement technique for microstrip patch antennas based on multi-pronged feed network synthesis

Developing antennas with enhanced gain has always been an important pursuit within the antenna community, as a higher gain leads to an increase in the received power for any given wireless link. In general, when a higher gain is needed for an application, only certain types of antennas can be used. The goal of this thesis project was to develop a method for increasing the gain of antennas that already exist by applying modifications to them, expanding the design flexibility for wireless applications. In this thesis, a novel method for increasing the gain of microstrip patch antennas by synthesizing specialized multi-branch feed networks is developed and verified experimentally. A full theoretical foundation based on cavity modal and radiation analysis is discussed followed by a detailed explanation of the feed network design, which culminates in the presentation of a start-to-finish full design workflow using MATLAB and ANSYS HFSS simulation. Four prototypes that were designed using this methodology are also presented, along with results that demonstrate the method’s efficacy as well as its tradeoffs. In addition, the MATLAB codes used in the design process are given, allowing the thesis to be used as a design guide

Affiliative Subgroups in Preschool Classrooms: Integrating Constructs and Methods from Social Ethology and Sociometric Traditions

Recent studies of school-age children and adolescents have used social network analyses to characterize selection and socialization aspects of peer groups. Fewer network studies have been reported for preschool classrooms and many of those have focused on structural descriptions of peer networks, and/or, on selection processes rather than on social functions of subgroup membership. In this study we started by identifying and describing different types of affiliative subgroups (HMP- high mutual proximity, LMP- low mutual proximity, and ungrouped children) in a sample of 240 Portuguese preschool children using nearest neighbor observations. Next, we used additional behavioral observations and sociometric data to show that HMP and LMP subgroups are functionally distinct: HMP subgroups appear to reflect friendship relations, whereas LMP subgroups appear to reflect common social goals, but without strong, within-subgroup dyadic ties. Finally, we examined the longitudinal implications of subgroup membership and show that children classified as HMP in consecutive years had more reciprocated friendships than did children whose subgroup classification changed from LMP or ungrouped to HMP. These results extend previous findings reported for North American peer groups

Affiliative Subgroups in Preschool Classrooms: Integrating Constructs and Methods from Social Ethology and Sociometric Traditions

Recent studies of school-age children and adolescents have used social network analyses to characterize selection and socialization aspects of peer groups. Fewer network studies have been reported for preschool classrooms and many of those have focused on structural descriptions of peer networks, and/or, on selection processes rather than on social functions of subgroup membership. In this study we started by identifying and describing different types of affiliative subgroups (HMP- high mutual proximity, LMP- low mutual proximity, and ungrouped children) in a sample of 240 Portuguese preschool children using nearest neighbor observations. Next, we used additional behavioral observations and sociometric data to show that HMP and LMP subgroups are functionally distinct: HMP subgroups appear to reflect friendship relations, whereas LMP subgroups appear to reflect common social goals, but without strong, within-subgroup dyadic ties. Finally, we examined the longitudinal implications of subgroup membership and show that children classified as HMP in consecutive years had more reciprocated friendships than did children whose subgroup classification changed from LMP or ungrouped to HMP. These results extend previous findings reported for North American peer groups

Sequencing and analysis of the gastrula transcriptome of the brittle star Ophiocoma wendtii

Background The gastrula stage represents the point in development at which the three primary germ layers diverge. At this point the gene regulatory networks that specify the germ layers are established and the genes that define the differentiated states of the tissues have begun to be activated. These networks have been well-characterized in sea urchins, but not in other echinoderms. Embryos of the brittle star Ophiocoma wendtii share a number of developmental features with sea urchin embryos, including the ingression of mesenchyme cells that give rise to an embryonic skeleton. Notable differences are that no micromeres are formed during cleavage divisions and no pigment cells are formed during development to the pluteus larval stage. More subtle changes in timing of developmental events also occur. To explore the molecular basis for the similarities and differences between these two echinoderms, we have sequenced and characterized the gastrula transcriptome of O. wendtii. Methods Development of Ophiocoma wendtii embryos was characterized and RNA was isolated from the gastrula stage. A transcriptome data base was generated from this RNA and was analyzed using a variety of methods to identify transcripts expressed and to compare those transcripts to those expressed at the gastrula stage in other organisms. Results Using existing databases, we identified brittle star transcripts that correspond to 3,385 genes, including 1,863 genes shared with the sea urchin Strongylocentrotus purpuratus gastrula transcriptome. We characterized the functional classes of genes present in the transcriptome and compared them to those found in this sea urchin. We then examined those members of the germ-layer specific gene regulatory networks (GRNs) of S. purpuratus that are expressed in the O. wendtii gastrula. Our results indicate that there is a shared ‘genetic toolkit’ central to the echinoderm gastrula, a key stage in embryonic development, though there are also differences that reflect changes in developmental processes. Conclusions The brittle star expresses genes representing all functional classes at the gastrula stage. Brittle stars and sea urchins have comparable numbers of each class of genes and share many of the genes expressed at gastrulation. Examination of the brittle star genes in which sea urchin orthologs are utilized in germ layer specification reveals a relatively higher level of conservation of key regulatory components compared to the overall transcriptome. We also identify genes that were either lost or whose temporal expression has diverged from that of sea urchins

Review: Creative Economies, Creative Communities: Rethinking Place, Policy, and Practice

The creative economy is studied by a variety of academic disciplines, and with their 2015 publication, English cultural geographers Saskia Warren and Phil Jones have taken an interdisciplinary approach, publishing work out of cultural and human geography, sociology, and public policy. The ten essays in Creative Economies, Creative Communities investigate who exactly benefits from public funding directed at growing the creative and cultural sectors

Public Life and Transit in the American South

The built form of cities in the American South has largely been defined and determined by the automobile. Achieving greater environmental sustainability, transit ridership, and social justice has thus often been a challenge in these cities. Two Southern cities: Charlotte, North Carolina and Atlanta, Georgia, introduced rail transit infrastructure after their built environments began to prioritize automobile movement over other transportation concerns. This research seeks to understand the daily human experience of transit station users and their relationship to their surroundings, and answers to what extent station areas are host to a rich and vibrant public life, as defined by the quality and quantity of optional and social activities taking place there. I found that the quality of public life is largely impaired in all four transit station areas I studied, due to a scarcity of overlapping activities in space and time, lack of eyes on the street, and plentiful, free parking.Bachelor of Art

Bacterial community profiles and Vibrio parahaemolyticus abundance in individual oysters and their association with estuarine ecology

Oysters naturally harbor the human gastric pathogen Vibrio parahaemolyticus, but the nature of this association is unknown. Because microbial interactions could influence the accumulation of V. parahaemolyticus in oysters, we investigated the composition of the microbiome in water and oysters at two ecologically unique sites in the Great Bay Estuary, New Hampshire using 16s rRNA profiling. We then evaluated correlations between bacteria inhabiting the oyster with V. parahaemolyticus abundance quantified using a most probable number (MPN) analysis. Even though oysters filter-feed, their microbiomes were not a direct snapshot of the bacterial community in overlaying water, suggesting they selectively accumulate some bacterial phyla. The microbiome of individual oysters harvested more centrally in the bay were relatively more similar to each other and had fewer unique phylotypes, but overall more taxonomic and metabolic diversity, than the microbiomes from tributary-harvested oysters that were individually more variable with lower taxonomic and metabolic diversity. Oysters harvested from the same location varied in V. parahaemolyticus abundance, with the highest abundance oysters collected from one location. This study, which to our knowledge is the first of its kind to evaluate associations of V. parahaemolyticus abundance with members of individual oyster microbiomes, implies that sufficient sampling and depth of sequencing may reveal microbiome members that could impact V. parahaemolyticus abundance

Handgun carrying among youth in the United States

Despite a wealth of research finding that adolescents who carry handguns are involved in risky behaviors, there has been little exploration into the heterogeneity of this behavior. Using a pooled sample of 12- to 17-year-olds from the National Study on Drug Use and Health who report past-year handgun carrying (N = 7,872), this study identified four subgroups of handgun carriers: low risk (n = 3,831; 47.93%), alcohol and marijuana users (n = 1,591; 20.16%), fighters (n = 1,430; 19.40%), and severe externalizers (n = 1,020, 12.51%). These subgroups differed on demographic, behavioral, and psychosocial characteristics. Findings are discussed in light of prevention and focused deterrence

L’influence du réseau affiliatif sur la répartition de l’attention sociale chez l’enfant en groupe préscolaire

Cette étude examine les variations dans l'allocation de l'attention sociale, en fonction des rôles sociaux des enfants d'âge préscolaire dans le réseau affiliatif de leur groupe. Les observations ont été réalisées auprès d'enfants de cinq ans, en automne, en hiver et au printemps de l'année scolaire en utilisant la technique du "voisin le plus proche". Les résultats révèlent de forts biais endogroupes dans la répartition de l'attention interpersonnelle. Des analyses complémentaires explorent les préférences des enfants pour des partenaires spécifiques et documentent la stratification des unités affiliatives. Les cliques de plus haut statut reçoivent comparativement plus l'attention des membres des autres sous-groupes d'affiliation. Ces résultats sont discutés par rapport à l'émergence des compétences sociales qui facilitent l'intégration des enfants dans le groupe préscolaire.This study examined changes in the allocation of social attention as a function of children's roles within the affiliative network of the preschool play group during the school year. Affiliative group structures were derived using a nearest neighbor data collected in the Fall, Winter and Spring sessions in a five-year old play group. Indices of allocation of attention revealed a strong endo-group bias throughout the school year. Secondary analyses examined the stratification of affiliative units in terms of children's preferences for particular playmates. Findings indicate that higher status cliques received a disproportionate amount of attention from other group members. Results are discussed in term of interactive strategies related to emerging social competence that promote individual integration within the peer group. It is argued that children who fail to develop these strategies may be at risk for peer rejection or peer neglect.Este estudio examina las variaciones en la reparticion de la atencion social en funcion de los roles sociales de los ninos de edad preescolar dentro de los grupos de afiliacion. Las obsevaciones han sido realizadas en ninos de cinco anos, en otono, en invierno y en la primavera del ano escolar, utilizando la técnica del "vecino mas cercano". Los resultados revelan fuertes desvios intragrupos en la reparticion de la atencion interpersonal. Analisis complementarios exploran las preferencias de los ninos por companeros especfficos y documentan la estratificacion de las unidades de afiliacion. Las pandillas consideradas con mayor status reciben comparativamente mas atencion de los miembros de los otros subgrupos de afiliacion. Estos resultados son discutidos en relacion a la emergencia de las competencias sociales que facilitan la integracion de los ninos en el grupo prescolar.Diese Studie untersucht die verschiedenen Varianten in der Zuwendung der Aufmerksamkeit im Hinblick auf die sozialen Rollen von Vorschulkindern im Rahmen ihrer Gruppenbindungen. Beobachtet wurden Kinder im Alter von funf Jahren jeweils im Herbst, Winter und Fiïihjahr des Vorschuljahres nach dem Kriterium des "besten Freundes". Aus den Ergebnissen geht hervor, dass es in der Verteilung der interpersonellen Aufmerksamkeit starke gruppeninterne Bewegungen gibt. In zusàtzlichen Analysen wurden die Vorlieben der Kinder fur bestimmte Partner sowie die Schichtung der Unter-gruppen untersucht und dokumentiert. Die Cliquen mit dem hôchsten Status erhalten von den Mitgliedern anderer Untergruppen vergleichsweise viel Aufmerksamkeit. Die Ergebnisse werden in Beziehung gesetzt zur Herausbildung sozialer Fahigkeiten, welche die Integration der Kinder in die Vorschulgruppe erleichtern