4,132 research outputs found

    Mixed Markov models applied for population changes in Spain

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    In this paper, common patterns of transition are tried to find in population. We look for chains in order to group Spanish provinces into clusters. Besides, income changes are analysed by the same procedure. Finally, we combine both studies to compare them Population and income data since 1960 to 1996 are collected form I.N.E. (National Spanish Institute of Statistics) databases.

    Data Access for LIGO on the OSG

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    During 2015 and 2016, the Laser Interferometer Gravitational-Wave Observatory (LIGO) conducted a three-month observing campaign. These observations delivered the first direct detection of gravitational waves from binary black hole mergers. To search for these signals, the LIGO Scientific Collaboration uses the PyCBC search pipeline. To deliver science results in a timely manner, LIGO collaborated with the Open Science Grid (OSG) to distribute the required computation across a series of dedicated, opportunistic, and allocated resources. To deliver the petabytes necessary for such a large-scale computation, our team deployed a distributed data access infrastructure based on the XRootD server suite and the CernVM File System (CVMFS). This data access strategy grew from simply accessing remote storage to a POSIX-based interface underpinned by distributed, secure caches across the OSG.Comment: 6 pages, 3 figures, submitted to PEARC1

    A totally laparoscopic associating liver partition and portal vein ligation for staged hepatectomy assisted with radiofrequency (radiofrequency assisted liver partition with portal vein ligation) for staged liver resection

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    In order to induce liver hypertrophy to enable liver resection in patients with a small future liver remnant, various methods have been proposed in addition to portal vein embolisation. Most recently, the ALPPS technique has gained significant international interest. This technique is limited by the high morbidity associated with an in-situ liver splitting and the patient undergoing two open operations. We present the case of a variant ALPPS technique performed entirely laparoscopically with no major morbidity or mortality. An increased liver volume of 57.9% was seen after 14 days. This technique is feasible to perform and compares favourably to other ALPPS methods whilst gaining the advantages of laparoscopic surgery

    Una mirada geométrica a la transformación de Box-Cox

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    En el análisis de los datos, cuando la normalidad no es un supuesto viable, una alternativa es ignorar los resultados del chequeo de normalidad y proceder como si los datos estuvieran normalmente distribuidos. Este procedimiento no es recomendable puesto que, en la mayoría de los casos, lleva a conclusiones incorrectas. Una segunda alternativa consiste en convertir los datos no normales en unos que tengan más apariencia de normales considerando transformaciones de los datos. Estas transformaciones son simplemente reexpresiones de los datos en diferentes unidades, frecuentemente sucede que las nuevas unidades proporcionan expresiones más naturales a las características que se están estudiando. Para datos normalmente distribuidos, las transformaciones lineales de los datos son comúnmente usadas para crear una variable con distribución normal estándar

    Assessment of secondary bubble formation on a backward-facing step geometry

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    Flow visualization experiments and numerical simulations were performed on a narrow three-dimensional backward-facing step (BFS) flow with the main objective of characterizing the secondary bubble appearing at the top wall. The BFS has been widely studied because of its geometrical simplicity as well as its ability to reproduce most of the flow features appearing in many applications in which separation occurs. A BFS test rig with an expansion ratio of 2 and two aspect ratios (AR = 4 and AR = 8) was developed. Tests were performed at range of Reynolds numbers ranging from 50 to 1000; visualization experiments provided a qualitative description of secondary bubble and wall-jet flows. Large eddy simulations were carried out with two different codes for validation. Numerical solutions, once validated with experimental data from the literature, were used to acquire a deeper understanding of the experimental visualizations, to characterize the secondary bubble as a function of the flow variables (Reynolds and AR) and to analyze the effect of the secondary bubble on primary reattachment length. Finally, to decouple the sidewall effects due to the non-slip condition and the intrinsic flow three-dimensionality, numerical experiments with free-slip conditions over the sidewalls were computed. The main differences were as follows: When the non-slip condition is used, the secondary bubble appears at a Reynolds number of approximately 200, increases with the Reynolds number, and is limited to a small part of the span. This recirculation zone interacts with the wall-jets and causes the maximum and minimum lengths in the reattachment line of the primary recirculation. Under free slip conditions, the recirculation bubble appears at a higher Reynolds number and covers the entire channel span. Published by AIP Publishing
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