4,329 research outputs found

    Charm Input for Determining gamma/phi_3

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    Overconstraining the CKM unitarity triangle with precision measurements of its angles continues to test the validity of the Standard Model. One of these angles, gamma/phi_3, has been measured by studying B+- -> D K+- decays, where D = D0 or D0-bar. I present recent results of hadronic D decays which will improve the sensitivity of gamma/phi_3 measurements.Comment: 4 pages, CIPANP 2009 proceedings; references adde

    Charm Factories: Present and Future

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    The next generation tau-charm factory, the third Beijing Electron Spectrometer (BESIII) at the new Beijing Electron Positron Collider (BEPCII), has begun data collection. I discuss the flavor physics reach of the BESIII charm program and conclude with a discussion on future proposed tau-charm facilities.Comment: 4 pages, CIPANP 2009 proceeding

    Análisis climático de la precipitación anual e interanual en la cuenca media del río Grande de San Ramón, Costa Rica

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    This project investigates three sectors located in the central basin of the río Grande San Ramón in Costa Rica. In spite of their proximity to each other, these stations show considerable variation, both temporal and spatial in intra- and interannual precipitation. This variation is attributed to regional atmospheric circulation patterns in the equatorial Pacific, producing strong precipitation during some years, and declines in others. There is a greater probability of lower annual precipitation during El Niño years and higher probabilities of large totals during La Niña years. The warm phase, El Niño, of the El Niño-Southern Oscillation phenomenon (ENSO) is more pronounced in Naranjo, which is located on the lower slope of the Central Volcanic Mountain range. The influence of regional/hemispherical cannot be regarded homogeneous in mountainous areas where local conditions may prevail.Se investigan tres sectores ubicados en la Cuenca media del río Grande de San Ramón en Costa Rica que a pesar de encontrarse muy cerca unos de otros, éstos muestran variaciones espacio temporales en la precipitación anual e interanual. Dicha variación se atribuye a patrones de circulación atmosféricos que influyen anualmente, produciendo fuertes precipitaciones durante unos años, mientras que en otros, se da más bien una disminución. Pareciera que existe una mayor probabilidad que ocurran promedios bajos de precipitación anual durante los años El Niño y promedios altos durante los años La Niña. De esta forma, la fase cálida es más marcada en aquellos lugares de topografía plana, en valles, que tienen una mayor influencia marítima y de corrientes de viento, como son los casos de Palmares y San Ramón, no así el caso de Naranjo que se ubica en las faldas de la Sección de la Cordillera Volcánica Central. Por lo tanto, se manifiestan variaciones en distancias cortas, o sea no se muestra un comportamiento homogéneo aún en regiones pequeñas

    Voting Alone: The Decline of Bodily Mass Communication and Public Sensationalism in Presidential Elections

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    The congregational crowd was a powerful mode of political communication in the nineteenth-century US until banished by the imposition of literate modes on popular electoral politics by Progressive reformers. We examine its major channels of expression, bodily mass communication and public sensationalism, within a framework of class-based struggle, observing that the practice of live bodily assembly created broad points of entry into political life, socialized the young, and successfully conveyed the importance of voting. A text-based normative model of the informed deliberative voter, we argue, offers too narrow a conception of participation compared to a more spaciously conceived democratic community

    Resolution and mass accuracy in matrix-assisted laser desorption ionization- time-of-flight

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    AbstractA mathematical model of time-of-flight mass analyzers employing uniform electric fields is presented that allows “exact” calculations of flight times as functions of mass-to-charge ratio, initial velocity and position, applied voltages, and instrument geometry. An “approximate” equation based on a series expansion of the “exact” result is derived which allows focusing conditions and limits on resolution to be determined for different instrument geometries and operating conditions. The fundamental theory is applied to predicting resolution and mass accuracy in matrix-assisted laser desorption ionization-time of flight. In this case higher order velocity focusing can provide excellent correction for the initial velocity distribution of a selected mass-to-charge ratio, but the focusing is mass-to-charge ratio dependent. There is generally a trade-off between ultimate resolution at a particular mass-to-charge ratio and resolution and mass accuracy over a broad mass range. In most practical applications the latter is more important. Calculations are compared with experimental results for a particular analyzer geometry, both at theoretical optimum velocity focus and at operating conditions where ultimate resolution is sacrificed for a broader range of relatively high resolution and better mass accuracy

    Zika Virus: Can Artificial Contraception Be Condoned?

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    As the Zika virus pandemic continues to bring worry and fear to health officials and medical scientists, Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) have recommended that residents of the Zika-infected countries, e.g., Brazil, and those who have traveled to the area should delay having babies which may involve artificial contraceptive, particularly condom. This preventive policy, however, is seemingly at odds with the Roman Catholic Church’s position on the contraceptive. As least since the promulgation of Paul VI’s 1968 encyclical, Humanae Vitae, the Church has explicitly condemned artificial birth control as intrinsic evil. However, the current pontiff, Pope Francis, during his recent visit to Latin America, remarked that the use of artificial contraception may not be in contradiction to the teaching of Humanae Vitae while drawing a parallel between the current Zika Crisis and the 1960’s Belgian Congo Nun Controversy. The pope mentioned that the traditional ethical principle of the lesser of two evils may be the doctrine that justified the exceptions. The authors of this paper attempt to expand the theological rationale of the pope’s suggestion. In so doing, the authors rely on casuistical reasoning as an analytic tool that compares the Belgian Congo Nun case and the given Zika case, and suggest that the former is highly similar to, if not the same as, the latter in terms of normative moral feature. That is, in both cases the use of artificial contraception is theologically justified in reference to the criteria that the doctrine of the lesser of two evils requires. The authors wish that the paper would provide a solid theological-ethical ground based on which condom-use as the most immediate and effective preventive measure can be recommended in numerous Catholic hospitals as well as among Catholic communities in the world, particularly the most Zika-affected and largest Catholic community in the world, Brazil – 123 million present Brazilian citizens are reported to be Roman Catholic

    Solar array construction

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    An interconnect tab on each cell of a first set of circular solar cells connects that cell in series with an adjacent cell in the set. This set of cells is arranged in alternate columns and rows of an array and a second set of similar cells is arranged in the remaining alternate columns and rows of the array. Three interconnect tabs on each solar cell of the said second set are employed to connect the cells of the second set to one another, in series and to connect the cells of the second set to those of the first set in parallel. Some tabs (making parallel connections) connect the same surface regions of adjacent cells to one another and others (making series connections) connect a surface region of one cell to the opposite surface region of an adjacent cell; however, the tabs are so positioned that the array may be easily assembled by depositing the cells in a certain sequence and in proper orientation

    Engineering MultiQueues: Fast relaxed concurrent priority queues

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    Priority queues with parallel access are an attractive data structure for applications like prioritized online scheduling, discrete event simulation, or greedy algorithms. However, a classical priority queue constitutes a severe bottleneck in this context, leading to very small throughput. Hence, there has been significant interest in concurrent priority queues with relaxed semantics. We investigate the complementary quality criteria rank error (how close are deleted elements to the global minimum) and delay (for each element x, how many elements with lower priority are deleted before x). In this paper, we introduce MultiQueues as a natural approach to relaxed priority queues based on multiple sequential priority queues. Their naturally high theoretical scalability is further enhanced by using three orthogonal ways of batching operations on the sequential queues. Experiments indicate that MultiQueues present a very good performance-quality tradeoff and considerably outperform competing approaches in at least one of these aspects. We employ a seemingly paradoxical technique of "wait-free locking" that might be of more general interest to convert sequential data structures to relaxed concurrent data structures
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