A Graph Theoretical Approach to the Dollar Game Problem

In this thesis we consider a problem in Graph Theory known as the Dollar Game. The Dollar game was first introduced by Matthew Baker of the Georgia Institute of Technology in 2010. It is a game of solitaire, played on a graph, and is a variation of chip firing, or sand-piling games. Baker approached the problem within the context of Algebraic Geometry. It is the goal of this paper to provide an overview of the necessary graph theory to understand the problem presented in this game, as well as background on chip firing games, their history and evolution. Finally we will present a variety of results about the Dollar Game from a graph theoretical standpoint

Isotopic ecology of coyotes from scat and road kill carcasses: A complementary approach to feeding experiments.

Scat is frequently used to study animal diets because it is easy to find and collect, but one concern is that gross fecal analysis (GFA) techniques exaggerate the importance of small-bodied prey to mammalian mesopredator diets. To capitalize on the benefits of scat, we suggest the analysis of scat carbon and nitrogen isotope values (δ13C and δ15N). This technique offers researchers a non-invasive method to gather short-term dietary information. We conducted three interrelated studies to validate the use of isotopic values from coyote scat: 1) we determined tissue-to-tissue apparent C and N isotope enrichment factors (ε13* and ε15*) for coyotes from road kill animals (n = 4); 2) we derived diet-to-scat isotope discrimination factors for coyotes; and 3) we used field collected coyote scats (n = 12) to compare estimates of coyote dietary proportions from stable isotope mixing models with estimates from two GFA techniques. Scat consistently had the lowest δ13C and δ15N values among the tissues sampled. We derived a diet-to-scat Δ13C value of -1.5‰ ± 1.6‰ and Δ15N value of 2.3‰ ± 1.3‰ for coyotes. Coyote scat δ13C and δ15N values adjusted for discrimination consistently plot within the isotopic mixing space created by known dietary items. In comparison with GFA results, we found that mixing model estimates of coyote dietary proportions de-emphasize the importance of small-bodied prey. Coyote scat δ13C and δ15N values therefore offer a relatively quick and non-invasive way to gain accurate dietary information

Coyote (Canis latrans) use of marine resources in coastal California: A new behavior relative to their recent ancestors

Coyotes ( Canis latrans) are known to consume marine foods, but the importance and persistence of marine subsidies to coyotes is unknown. Recent access to a marine subsidy, especially if gained following apex predator loss, may facilitate coyote expansion along coastal routes and amplify the effects of mesopredator release. Our goal was to quantify and contextualize past and present marine resource use by coyotes on the central coast of California via stable isotope analysis. We measured δ13C and δ15N values in coyotes, their competitors, and their food resources at two modern sites, seven archaeological sites spanning in age from ~3000 to 750 BP, and from historical (AD 1893–1992) coyote and grizzly bear hair and bone sourced from coastal counties. We found evidence for marine resource use by modern coastal California coyotes at one site, Año Nuevo, which hosts a mainland northern elephant seal ( Mirounga angustirostris) breeding colony. Seals and sea lions account for ~20% of Año Nuevo coyote diet throughout the year and this marine subsidy likely positively impacts coyote population size. Isotopic data suggest that neither historic nor prehistoric coyotes consumed marine-derived foods, even at sites near ancient mainland seal rookeries. Marine resource use by some contemporary California coyotes is a novel behavior relative to their recent ancestors. We hypothesize that human alteration of the environment through extirpation of the California grizzly bear and the more recent protection of marine mammals likely enabled this behavioral shift

Transcriptomics Reveals the Putative Mycoparasitic Strategy of the Mushroom Entoloma abortivum on Species of the Mushroom Genus Armillaria

During mycoparasitism, a fungus—the host—is parasitized by another fungus—the mycoparasite. The genetic underpinnings of these relationships have been best characterized in ascomycete fungi. However, within basidiomycete fungi, there are rare instances of mushroom-forming species parasitizing the reproductive structures, or sporocarps, of other mushroom-forming species, which have been rarely investigated on a genetic level. One of the most enigmatic of these occurs between Entoloma abortivum and species of Armillaria, where hyphae of E. abortivum are hypothesized to disrupt the development of Armillaria sporocarps, resulting in the formation of carpophoroids. However, it remains unknown whether carpophoroids are the direct result of a mycoparasitic relationship. To address the nature of this unique interaction, we analyzed gene expression of field-collected Armillaria and E. abortivum sporocarps and carpophoroids. Transcripts in the carpophoroids are primarily from E. abortivum, supporting the hypothesis that this species is parasitizing Armillaria. Most notably, we identified differentially upregulated E. abortivum b-trefoil-type lectins in the carpophoroid, which we hypothesize bind to Armillaria cell wall galactomannoproteins, thereby mediating recognition between the mycoparasite and the host. The most differentially upregulated E. abortivum transcripts in the carpophoroid code for oxalate decarboxylases—enzymes that degrade oxalic acid. Oxalic acid is a virulence factor in many plant pathogens, including Armillaria species; however, E. abortivum has evolved a sophisticated strategy to overcome this defense mechanism. The number of gene models and genes that code for carbohydrate-active enzymes in the E. abortivum transcriptome was reduced compared to other closely related species, perhaps as a result of the specialized nature of this interaction

Long-Term Dietary Nitrate Supplementation Does Not Prevent Development of the Metabolic Syndrome in Mice Fed a High-Fat Diet

Background. Nitric oxide (NO) is an important vascular signaling molecule that plays a role in vascular homeostasis. A reduction in NO bioavailability is thought to contribute to endothelial dysfunction, an early risk factor for both cardiovascular disease and type 2 diabetes. Dietary nitrate, through the nitrate-nitrite-NO pathway, may provide an alternate source of NO when the endogenous eNOS system is compromised. In addition to a role in the vascular system, NO may also play a role in the metabolic syndrome including obesity and glucose tolerance. Aim. To investigate the effect of long-term dietary nitrate supplementation on development of the metabolic syndrome in mice fed a high-fat diet. Methods. Following 1 week of acclimatisation, male (6-8 weeks) C57BL6 mice were randomly assigned to the following groups (10/group) for 12 weeks: (i) normal chow + NaCl (1 mmol/kg/day), (ii) normal chow + NaNO3 (1 mmol/kg/day), (iii) high-fat diet + NaCl (1 mmol/kg/day), and (iv) high-fat diet + NaNO3 (1 mmol/kg/day). Body weight and food consumption were monitored weekly. A subset of mice (5/group) underwent running wheel assessment. At the end of the treatment period, all mice underwent fasting glucose tolerance testing. Caecum contents, serum, and tissues (liver, skeletal muscle, white and brown adipose, and kidney) were collected, frozen, and stored at -80°C until analysis. Results. Consumption of the high-fat diet resulted in significantly greater weight gain that was not affected by dietary nitrate. Mice on the high-fat diet also had impaired glucose tolerance that was not affected by dietary nitrate. There was no difference in adipose tissue expression of thermogenic proteins or energy expenditure as assessed by the running wheel activity. Mice on the high-fat diet and those receiving dietary nitrate had reduced caecum concentrations of both butyrate and propionate. Conclusions. Dietary nitrate does not prevent development of the metabolic syndrome in mice fed a high-fat diet. This may be due, in part due, to reductions in the concentration of important short-chain fatty acids

Космоструктурные позиции золоторудных объектов заангарской части Енисейского кряжа

Изучены космоструктуры заангарский части Енисейского кряжа по материалам мультиспектральных космических систем Modis и Landsat ETM+. Выделены четыре системы кольцевых структур первого порядка, интерпретируемые как глубинные очаги гранитизации. Показаны закономерности размещения золотого оруденения в космогеологических структурах. Выделенные разноранговые космогеологические структуры находят отражение в аномальных структурах геохимических полей

Social and Psychological Factors Associated with Health Care Transition for Young Adults Living with Sickle Cell Disease

Introduction: Due to advances in disease management, mortality rates in children with sickle cell disease (SCD) have decreased. However, mortality rates for young adults (YA) increased, and understanding of social and psychological factors is critical. The aim of this study was to explore factors associated with health care transition experiences for YA with SCD. Method: This was a qualitative descriptive study. A 45-minute semistructured interview was conducted with 13 YA (M = 21.5 years, SD = 1.73). Results: Results suggest that social and psychological factors and self-management experiences influence health care transition. Eight themes emerged: “need for accessible support”; “early assistance with goal setting”; “incongruence among expectations, experiences, and preparation”; “spiritual distress”; “stigma”; “need for collaboration”; “appreciation for caring providers”; and “feeling isolated.” Discussion: Consideration of cultural contexts will guide nurses in supporting health care transition. Designing culturally relevant interventions that address unique needs for YA living with SCD is warranted