Identifying Influentials in Directed Networks

Research into the identification of influential nodes specifically with regards to weighted, directed networks has been lacking throughout the lifetime of Network Theory as a whole. This research project seeks to propel the field forward through by devising an algorithm aimed at identifying influential nodes through the use of probability propagation models of information transfer through various real-world networks. The networks discussed are a developed test-network using the Price Model of citation network growth, the neuronal connectivity network of the flatworm C. elegans, and Congressional co-sponsorship networks of the USA’s 110th House and Senate. Rankings of influence of each node, as determined by the developed algorithm, were then compared to ground truth rankings of influence determined by Susceptible-Infected-Recovered (SIR) model simulations via the Kendall’s Tau-b statistical measurement, so as to determine the reliability and accuracy of the developed algorithm’s probabilistic approach to influence. To this end, the research finished off by examining how the developed algorithm’s results compare to that of well-known influence calculation mechanisms, such as Google’s PageRank

Blood flow, not hypoxia, determines intramucosal PCO(2)

Monitoring tissue hypoxia in critically ill patients is a challenging task. Tissue PCO(2 )has long been proposed as a marker of tissue hypoxia, although there is considerable controversy on whether the rise in CO(2 )with hypoxia is caused by anaerobic metabolism and excess CO(2 )production or by the accumulation of aerobically produced CO(2 )in the setting of blood flow stagnation. The prevention of increases in intestinal PCO(2 )in aggressively resuscitated septic animals supports the notion that tissue CO(2 )accumulation is a function of decreases in blood flow, not of tissue hypoxia

Information requirements for strategic decision making: energy market

Over the last two decades, the electricity sector has been involved in a challenging restructuring process in which the vertical integrated structure (monopoly) is being replaced by a horizontal set of companies. The growing supply of electricity, flowing in response to free market pricing at the wellhead, led to increased competition. In the new framework of deregulation, what characterizes the electric industry is a commodity wholesale electricity marketplace. This new environment has drastically changed the objective of electricity producing companies. In the vertical integrated industry, utilities were forced to meet all the demand from customers living in a certain region at fixed rates. Then, the operation of the Generation Companies (GENCOs) was centralized and a single decision maker allocated the energy services by minimizing total production costs. Nowadays, GENCOs are involved not only in the electricity market but also in additional markets such as fuel markets or environmental markets. A gas or coal producer may have fuel contracts that define the production limit over a time horizon. Therefore, producers must observe this price levels in these other markets. This is a lesson we learned from the Electricity Crisis in California. The Californian market\u27s collapse was not the result of market decentralization but it was triggered by other decisions, such as high natural gas prices, with a direct impact in the supply-demand chain. This dissertation supports generation asset business decisions -from fuel supply concerns to wholesale trading in energy and ancillary services. The forces influencing the value chain are changing rapidly, and can become highly controversial. Through this report, the author brings an integrated and objective perspective, providing a forum to identify and address common planning and operational needs. The purpose of this dissertation is to present theories and ideas that can be applied directly in algorithms to make GENCOs decisions more efficient. This will decompose the problem into independent subproblems for each time interval. This is preferred because building a complete model in one time is practically impossible. The diverse scope of this report is unified by the importance of each topic to understanding or enhancing the profitability of generation assets. Studies of top strategic issues will assess directly the promise and limits to profitability of energy trading. Studies of ancillary services will permit companies to realistically gauge the profitability of different services, and develop bidding strategies tuned to competitive markets

The effect of nutrition and metabolic hormones on follicular development in cattle

Nutrition has profound effects on reproductive performance in cattle. Although these effects have been documented, the underlying mechanisms are not yet fully understood. The aim of this project was to investigate the role of metabolic hormones in mediating these nutritional effects by studying bovine folliculogenesis. The interaction of metabolic hormones and gonadotrophins on granulosa cell function in vitro was also investigated.To determine the effect of nutrition on ovarian follicular development, twenty -eight heifers were allocated to different dietary treatments. Small follicle number ( 8mm) follicles and FSH concentrations were not different among treatments.The relationship between postpartum follicular development and endocrine and metabolic changes in lines selected for high or low predicted breeding value for milk yield (PBV) was investigated. PBV was strongly correlated with milk production during a 305 day -lactation. This was associated with higher peripheral GH and ß- hydroxybutyrate, and lower insulin and glucose concentrations in high genetic merit cows. Although no differences were seen in follicular development between selection lines, changes in body weight influenced follicle number, and day to first ovulation postpartum was delayed in cows selected for high milk production.To gain an insight into the mechanisms underlying the nutritional effect on folliculogenesis, a serum -free bovine granulosa cell culture system was developed. In the presence of FSH, granulosa cells from small follicles differentiated in vitro and oestradiol (E,) secretion increased with time. Cells from medium -sized and large follicles secreted E2 throughout the culture period. Insulin and FSH promoted proliferation and E, production in a dose -responsive manner. The inclusion of IGF -I enhanced proliferation and E, production, even in the absence of FSH. Furthermore, cultured granulosa cells formed clumps of spherical cells with ultrastructural characteristics that resembled those of granulosa cells in vivo. In contrast, granulosa cells growing either in the base of the clump, or as monolayers on serum- coated wells, possessed morphological characteristics suggestive of early luteinisation.The interaction of IGF -I and insulin on granulosa cell proliferation and E, production in vitro was determined in cells from follicles from cattle without or with a dominant follicle in vivo, i.e. ovaries were collected either on day 3 or day 7 of the oestrous cycle respectively. E, production and proliferative capacity of granulosa cells from medium -sized follicles in vitro was inhibited by the presence of a dominant follicle during their development in vivo. However, after long -term culture, E, production did not differ between granulosa cells either from day 3 or from day 7 follicles, but there were differences in proliferative responses to FSH and IGF -I according to the size of the follicle and the stage of the follicular wave.The effects of FSH, EGF and IGF -I on early follicular development were studied by culturing preantral follicles. Follicle and oocyte diameter increased with time in culture. FSH, IGF -I and EGF stimulated follicle growth, but not oocyte growth rate. Most follicles maintained their morphology throughout culture and antra developed after 10 to 28 days of culture. EGF, IGF -I and FSH increased the probability of antrum developmentThese results demonstrate that insulin and IGF -I, but not GH, may mediate the direct effects of nutrition on follicular development. IGFs may also have an autocrine action in the follicle, being tightly regulated by the production of IGF -BPs within the follicle.IGFs, as mediators of steroidogenesis and proliferation of granulosa cells, can act through endocrine, autocrine and/or paracrine mechanisms. Neither insulin nor FSH induced detectable levels of IGF -I production in granulosa cells, but IGF- binding proteins were secreted. IGF -I mRNA expression was found in theca cells, but not in granulosa cells either before or after culture. In contrast, IGF -II was expressed in both theca and granulosa cells

TMbarrier: speculative barriers using hardware transactional memory

Barrier is a very common synchronization method used in parallel programming. Barriers are used typically to enforce a partial thread execution order, since there may be dependences between code sections before and after the barrier. This work proposes TMbarrier, a new design of a barrier intended to be used in transactional applications. TMbarrier allows threads to continue executing speculatively after the barrier assuming that there are not dependences with safe threads that have not yet reached the barrier. Our design leverages transactional memory (TM) (specifically, the implementation offered by the IBM POWER8 processor) to hold the speculative updates and to detect possible conflicts between speculative and safe threads. Despite the limitations of the best-effort hardware TM implementation present in current processors, experiments show a reduction in wasted time due to synchronization compared to standard barriers.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech