Atrial fibrillation: diagnosis and management

This guideline covers diagnosing and managing atrial fibrillation in adults. It includes guidance on providing the best care and treatment for people with atrial fibrillation, including assessing and managing risks of stroke and bleeding

Demonstration of Tissue Factor expression using a Tissue Factor – Green Fluorescent Protein Reporter Model

Blood coagulation is initiated when circulating factor (F) VII comes into contact with membrane bound tissue factor (TF). Subsequently a series of enzymatic cleavages results in the formation of insoluble fibrin. The coagulation network is of fundamental importance in maintaining the integrity of the circulation and is closely integrated with other processes such as inflammation. Both under- and over-activity of the network have significant pathological consequences and thus the network is tightly regulated. The first point of regulation is in the formation of the TF•FVIIa initiating complex. Circulating FVII is kept separate from membrane-bound TF by an intact vascular wall. The initiation of coagulation is thus dependant on the site of TF expression. In addition abnormal TF expression has been shown to be important in various pathological processes such as atherosclerosis and cancer metastasis. The accurate demonstration of TF activity is of critical importance in the understanding of these processes. This thesis describes the development of a TF-Enhanced Green Fluorescent Protein (EGFP) reporter model for analysis of TF expression. A targeting vector containing the cDNA for EGFP in-frame with and flanked by regions homologous to the mouse TF gene was generated. The vector was designed such that EGFP would be knocked in to the TF locus by homologous recombination to produce a fusion protein with EGFP tagged onto the intact cytoplasmic domain of TF. Two strategies were used for generating transgenic mice. A targeting vector was electroporated into mouse embryonic stem (ES) cells and correctly targeted ES cells were then used in blastocyst injections. Alternatively a bacterial artificial chromosome (BAC) containing the mouse TF gene and flanking regions was targeted in a bacterial host using a similar vector. The targeted BAC was used in pro-nuclear injections of fertilized mouse ova resulting in random integration into the mouse genome. The function of the TF-EGFP reporter model was investigated by analysis of transgene expression in whole tissues and specific cell types taken from transgenic mice

Biogeochemical Changes During Bio-cementation Mediated by Stimulated and Augmented Ureolytic Microorganisms.

Microbially Induced Calcite Precipitation (MICP) is a bio-mediated cementation process that can improve the engineering properties of granular soils through the precipitation of calcite. The process is made possible by soil microorganisms containing urease enzymes, which hydrolyze urea and enable carbonate ions to become available for precipitation. While most researchers have injected non-native ureolytic bacteria to complete bio-cementation, enrichment of native ureolytic microorganisms may enable reductions in process treatment costs and environmental impacts. In this study, a large-scale bio-cementation experiment involving two 1.7-meter diameter tanks and a complementary soil column experiment were performed to investigate biogeochemical differences between bio-cementation mediated by either native or augmented (Sporosarcina pasteurii) ureolytic microorganisms. Although post-treatment distributions of calcite and engineering properties were similar between approaches, the results of this study suggest that significant differences in ureolysis rates and related precipitation rates between native and augmented microbial communities may influence the temporal progression and spatial distribution of bio-cementation, solution biogeochemical changes, and precipitate microstructure. The role of urea hydrolysis in enabling calcite precipitation through sustained super-saturation following treatment injections is explored

Learning and Noisy Equilibrium Behavior in an Experimental Study of Imperfect Price Competition

This paper considers a duopoly price-choice game in which the unique Nash equilibrium is the Bertrand outcome. Price competition, however, is imperfect in the sense that the market share of the high-price firm is not zero. Economic intuition suggests that price levels should be positively related to the market share of the high-price firm. Although this relationship is not predicted by standard game theory, it is implied by a generalization of the Nash equilibrium that results when players make noisy (logit) best responses to expected payoff differences. This logit equilibrium model was used to design a laboratory experiment with treatments that correspond to changing the market share of the high-price firm. The model predicts the final-period price averages for both treatments with remarkable accuracy. Moreover computer simulations of a naive learning model were used, ex ante, to predict the observed differences in the time paths of average prices.laboratory experiments, simulation, decision error, learning, logit equilibrium.

Circulación, intercambio y uso de obsidianas en la costa de la provincia del Chubut (Patagonia argentina), durante el Holoceno tardío

Se presentan los resultados de un nuevo análisis de elementos traza en veintiséis artefactos de diecinueve sitios arqueológicos de la costa de la provincia del Chubut. Dieciocho sitios son del sector norte, entre las desembocaduras del Arroyo Verde y del Río Chubut, y el último está situado al sur, en Cabo Dos Bahías. Seis diferentes tipos de obsidiana fueron identificados; tres de ellos de fuentes conocidas: los tipos T/SCI de la fuente de Telsen y SI de la fuente Sacanana, ambas del centro-norte de la provincia del Chubut (Stern et al. 2000), y el tipo PDAI de la fuente de Pampa del Asador, en la provincia de Santa Cruz (Stern 1999). Los tipos de fuente desconocida son: CC? anteriormente determinado en un sitio arqueológico de Cerro Castillo, margen sudoeste de la Meseta de Somuncurá; el tipo T/SCII, en principio considerado como subtipo de la fuente de Telsen, pero según estos nuevos análisis, pertenece a una fuente distinta; y un tipo nuevo, MSI, cuya fuente estaría en la Meseta de Somuncurá. La información aquí presentada indica que los seis diferentes tipos de obsidiana llegaron a la costa central de Patagonia desde centros de aprovisionamiento independientes y desde distancias variables entre 100 km y 800 km.The results of analyses of trace-elements in twenty-six samples of obsidian from nineteen archaeological sites along the Atlantic coast, between Golfo San Matías Oeste (41°55´58.8´´S) and Cabo Dos Bahías (44°54´77.9´´S) are presented as a contribution to studies of sources and distribution of obsidian in archaeological sites in central Patagonia, specifically the province of Chubut, Argentina. Six different types of obsidian occur in this collection, three of which come from known obsidian sources. Four of the samples are chemically similar to obsidian type T/SCI, which is derived from near Sierra Negra (42°21’S – 66°36´W), northeast of the town of Telsen, and is located between 100 and 235 km linear distance west of the sites along the coast in which this obsidian occurs. Five of the samples are chemically similar to obsidian type SI from the vicinity of Cerro Guacho (42°28´60´´S – 68°32´93´´W) in the zone of Sacanana, and which is found between 270 and 400 km linear distance west of the sites along the coast in which this obsidian occurs. Finally, one sample from the site Cabo Dos Bahías has chemical characteristics similar to type PDAI obsidian from Pampa del Asador, in the Andean foothills of central-south Patagonia, Santa Cruz Province. Another sample of obsidian from this same source had previously been reported from a site near Puerto Madryn, along the coast of Golfo Nuevo, 800 km from Pampa del Asador. Concerning the samples from unknown sources, five samples are of an obsidian type which also occurs commonly in sites on and west of the Meseta de Somuncurá. The source is therefore believed to lie somewhere within the area of this Meseta. This type of obsidian is tentatively called type MS1. Two samples are chemically similar to obsidian type CCI? found at the archaeological site Cerro Castillo on the western edge of Meseta de Somuncurá. Nine samples are obsidian type T/SCII, previously believed to be from the same source near Sierra Negra as type T/SCI. However, a new analysis of samples from this area indicates that it is not the source of T/SCII, and the actual source of this obsidian, which is both more abundant and more widely distributed that type T/SCI, is unknown. The data indicate that different types of obsidian reached the coast from a number of independent locations between 100 km and 800 km to the West and SouthwestFil: Gomez Otero, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Stern, Charles. State University of Colorado at Boulder; Estados Unido

Nonfixed Retirement Age for University Professors: Modeling Its Effects on New Faculty Hires

We model the set of tenure-track faculty members at a university as a queue, where “customers” in queue are faculty members in active careers. Arrivals to the queue are usually young, untenured assistant professors, and departures from the queue are primarily those who do not pass a promotion or tenure hurdle and those who retire. There are other less-often-used ways to enter and leave the queue. Our focus is on system effects of the elimination of mandatory retirement age. In particular, we are concerned with estimating the number of assistant professor slots that annually are no longer available because of the elimination of mandatory retirement. We start with steady-state assumptions that require use of Little's Law of Queueing, and we progress to a transient model using system dynamics. We apply these simple models using available data from our home university, the Massachusetts Institute of Technology.United States. National Institutes of Health (5U01GM094141-02

Magnified Effects of Changes in NIH Research Funding Levels

What happens within the university-based research enterprise when a federal funding agency abruptly changes research grant funding levels, up or down? We use simple difference equation models to show that an apparently modest increase or decrease in funding levels can have dramatic effects on researchers, graduate students, postdocs, and the overall research enterprise. The amplified effect is due to grants lasting for an extended period, thereby requiring the majority of funds available in one year to pay for grants awarded in previous years. We demonstrate the effect in various ways, using National Institutes of Health data for two situations: the historical doubling of research funding from 1998 to 2003 and the possible effects of “sequestration” in January 2013. We posit human responses to such sharp movements in funding levels and offer suggestions for amelioration.National Institute of General Medical Sciences (U.S.) (Grant 5U01GM094141-02