Cohomogeneity-one G2-structures

G2-manifolds with a cohomogeneity-one action of a compact Lie group G are studied. For G simple, all solutions with holonomy G2 and weak holonomy G2 are classified. The holonomy G2 solutions are necessarily Ricci-flat and there is a one-parameter family with SU(3)-symmetry. The weak holonomy G2 solutions are Einstein of positive scalar curvature and are uniquely determined by the simple symmetry group. During the proof the equations for G2-symplectic and G2-cosymplectic structures are studied and the topological types of the manifolds admitting such structures are determined. New examples of compact G2-cosymplectic manifolds and complete G2-symplectic structures are found.Comment: 23 page

Migrant stopover ecology and resident resilience after hurricane Iris in a neotropical bird community

Thesis (M.S.) University of Alaska Fairbanks, 2003I conducted two avian ecology studies in southern Belize. I examined mass gains by Nearctic-Neotropic migrants in forest near the Gulf of Honduras, a potential ecological barrier to migration. Condition indices (mass/wing chord or tail length) were used to estimate net diel mass gains in migrant species. Ten migrant species apparently were fattening at the site, but some species not fattening at the site had accumulated fat loads elsewhere, and this region appears to provide important resources for transient migrants. I also studied the resilience of a marked resident bird community after Hurricane Iris severely altered the habitat. Given the severity of the disturbance, I expected that the bird community would have been severely impacted. Resident species were combined into ecological guilds, and patterns of captures and recaptures were compared before and after the hurricane. In resident species, survivors played an important role in the resilience of the community. Species abundances shifted, and the amount of fat that birds were carrying after the hurricane increased significantly. Despite the severe habitat alteration, local species extirpations were minimal, although the community was still changing one year after the storm

Liquid crystalline properties of unsymmetrically substituted phthalocyanines: structural features leading to nematic mesophase materials

A novel homologous series of four 1,4,8,11,15,18-hexakis(pentyl)-22-methyl-25-hydroxyalkylphthalocyanine derivatives with the hydroxyalkyl chain varying from hydroxynonyl through to hydroxydodecyl has been synthesized to investigate the role of the hydroxyalkyl chain in promoting thermotropic liquid crystalline behavior. Polarizing optical miscoscopy reveals that the compound with the shortest hydroxyalkyl chain (hydroxynonyl) exhibits a mesophase with a texture characteristic of a columnar mesophase, common among liquid crystalline phthalocyanine derivatives. However, as the chain is lengthened along the series, there appears a second type of mesophase that shows a schlieren texture. Such a texture is characteristic of a nematic phase and rare among liquid crystalline phthalocyanine derivatives. A fifth compound, the novel 1,4,8,11,15,18-hexakis(pentyl)-22-methyl-25- dodecylphthalocyanine, exhibits only columnar mesophase behavior suggesting that the hydroxyl group at the end of the longer chains of the former compounds is important in developing the nematic phase

Population Genetics and Colony Breeding Structure of the Invasive Tawny Crazy Ant, Nylanderia fulva

Insects that have evolved to live socially are some of the most invasive species on the planet. Of these invaders, many are ant species whose overwhelming success in non-native habitats is possible due to several favorable attributes. Unicoloniality, a social structure adopted by many invasive ant species, is defined by the ability to form supercolonies (a group of individuals throughout a geographic area, where direct interaction of individuals from distant nests does not occur) which may span many kilometers. High queen densities within supercolonies affords an overpowering concentration of worker ants which intermix with members of adjacent colonies without intraspecific aggression, seemingly working together resulting in exponential colony growth. The tawny crazy ant, Nylanderia fulva (Mayr), was recently introduced into the southeastern United States from South America. These ants were first discovered in Texas in 2002 and were possibly introduced into Florida as early as the 1950s. Since then, this invasive ant pest has spread to all southeastern Gulf States where it outcompetes native species, reduces arthropod species diversity, and infests urban, agricultural, and natural areas. Colonies of this ant are believed to be unicolonial in invasive populations, but to date this has not been explicitly investigated. Through behavioral assays and genetic analyses, I tested the hypothesis that the tawny crazy ant is unicolonial in its invasive range and estimated the number of possible introductions into the United States. In this study, I conclude that the tawny crazy ant is, in fact, unicolonial throughout its invasive range. I found no evidence of population differentiation, even among populations hundreds of kilometers apart. I also found low levels of relatedness (r = 0) among nestmates, lack of inbreeding, and an absence of aggression between nonnestmates separated over hundreds of km. I also discovered evidence of weak isolation by distance across the Gulf States. These results show that N. fulva forms a single supercolony throughout the entire invasive range of the southeastern United States that is most likely the result of a single introduction, which then spread via human mediated dispersal and colony budding

Effect of Electrode Placement on Defibrillation Threshold and Esophageal Electric Field in Internal Atrial Defibrillation

Atrial fibrillation is the most common heart arrhythmia of clinical significance. Internal cardioversion can be used to restore sinus rhythm; however, the amount of delivered energy elicits intolerable pain. Lowering delivered energy could make implantable cardioverters a promising treatment option. This study simulated cardioversion shocks in a model of the human heart using finite element analysis to determine effects of different electrode placements on defibrillation threshold (DFT) and esophageal electric field (EEF) near the left atrium. Ten right atrial to coronary sinus electrode placements were tested. Small shifts in electrode placements changed DFT by up to 42%, indicating electrode position is an important factor in lowering DFT. A relationship was not discovered between EEF and DFT. If a relationship can be discovered between an alternate EEF or other measure and DFT, electrode placements could be optimized on a patient-specific basis to lower delivered energy to painless or tolerable levels

An exploration and comparison of food and drink availability in homes in a sample of families of White and Pakistani origin within the UK.

OBJECTIVE: Knowledge of the types and quantities of foods and drinks available in family homes supports the development of targeted intervention programmes for obesity prevention or management, or for overall diet improvement. In the UK, contemporary data on foods that are available within family homes are lacking. The present study aimed to explore home food and drink availability in UK homes. DESIGN: An exploratory study using researcher-conducted home food availability inventories, measuring all foods and drinks within the categories of fruits, vegetables, snack foods and beverages. SETTING: Bradford, a town in the north of the UK. SUBJECTS: Opportunistic sample of mixed ethnicity families with infants approximately 18 months old from the Born in Bradford birth cohort. RESULTS: All homes had at least one type of fruit, vegetable and snack available. Fresh fruits commonly available were oranges, bananas, apples, satsumas and grapes. Commonly available fresh vegetables included potatoes, cucumber, tomatoes and carrots. The single greatest non-fresh fruit available in homes was raisins. Non-fresh vegetables contributing the most were frozen mixed vegetables, tinned tomatoes and tinned peas. Ethnic differences were found for the availability of fresh fruits and sugar-sweetened beverages, which were both found in higher amounts in Pakistani homes compared with White homes. CONCLUSIONS: These data contribute to international data on availability and provide an insight into food availability within family homes in the UK. They have also supported a needs assessment of the development of a culturally specific obesity prevention intervention in which fruits and vegetables and sugar-sweetened beverages are targeted

Keeping control : relations between men's gender role conflict, spirituality and psychological well being

Title from PDF of title page (University of Missouri--Columbia, viewed on March 3, 2011).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Glenn Good.Vita.Ph. D. University of Missouri--Columbia 2010.Recent decades have seen an increase in scrutiny of masculinity and what it means to be a man in society. Researchers as well as popular culture have increased their focus on gender roles and how those roles can create internal and interpersonal conflicts in men. In addition, spirituality has become an increasingly salient variable for clinicians and researchers assessing overall psychological well-being. The current study explored the ability of gender role conflict and spiritual attitudes to predict psychological wellbeing among men. Participants were 223 college-aged men whom were either members of Christian organizations or fraternities on the campus of a large public university in the Midwest. Several variables of gender role conflict and spiritual attitudes were significantly related to psychological well-being. Increased gender role conflict combined with maladaptive spiritual attitudes were predictive of lower overall psychological well-being. Limitations and implications for practice and research are discussed.Includes bibliographical reference

University Opportunities, Abilities and Motivations to Create Data Analytics Programs

Some US colleges and universities have developed undergraduate and graduate data analytics programs in the past five years, but not all universities appear to have sufficient resources and incentives to venture into this multidisciplinary academic area. The purpose of this study is to identify the characteristics of schools that have developed data analytics programs. The study utilizes the motivation-ability-opportunity (MAO) theoretical framework to identify factors that increase the likelihood that a university will develop a data analytics program. An analysis of 391 regional master’s universities in the US finds that schools with data analytics programs are more likely to be in larger cities and have larger student enrollments, better educational quality rankings, and an existing statistics and/or actuarial science program. These findings support the idea that data analytics programs are more likely to be created when universities have opportunities to access a larger number of businesses and governmental organizations, and sufficient resources to support program development, while also having abilities associated with innovation and faculty resources. Preliminary results also indicate that there are two motivations – need to increase student enrollment and need to maintain an up-to-date curriculum

Explanations for the Predominant Use of Cash Financing in Hospitality Acquisitions

Seventy-five percent of hospitality acquisitions were cash-financed from 1980 to 2000. In other industries this figure has been closer to 43%. Since the choice of cash versus stock financing can have a significant effect on a hospitality acquire‘s capital structure, the purpose of this study was to examine possible explanations for the high level of cash financing used in hospitality acquisitions. The results indicate that in both the hotel and restaurant industries, the use of cash payments in acquisi-tions is positively related to the acquiring firm’s debt ratio. Firm size is also positively related to the use of cash payments but only in the restaurant industry. Free cash flow and internal growth opportunities do not appear to be significant determinants of the use of cash payments in acquisitions in the hospitality industry