A Taxonomy of Workflow Management Systems for Grid Computing

With the advent of Grid and application technologies, scientists and engineers are building more and more complex applications to manage and process large data sets, and execute scientific experiments on distributed resources. Such application scenarios require means for composing and executing complex workflows. Therefore, many efforts have been made towards the development of workflow management systems for Grid computing. In this paper, we propose a taxonomy that characterizes and classifies various approaches for building and executing workflows on Grids. We also survey several representative Grid workflow systems developed by various projects world-wide to demonstrate the comprehensiveness of the taxonomy. The taxonomy not only highlights the design and engineering similarities and differences of state-of-the-art in Grid workflow systems, but also identifies the areas that need further research.Comment: 29 pages, 15 figure

Emergence of hyperons in failed supernovae: trigger of the black hole formation

We investigate the emergence of strange baryons in the dynamical collapse of a non-rotating massive star to a black hole by the neutrino-radiation hydrodynamical simulations in general relativity. By following the dynamical formation and collapse of nascent proto-neutron star from the gravitational collapse of a 40Msun star adopting a new hyperonic EOS table, we show that the hyperons do not appear at the core bounce but populate quickly at ~0.5-0.7 s after the bounce to trigger the re-collapse to a black hole. They start to show up off center owing to high temperatures and later prevail at center when the central density becomes high enough. The neutrino emission from the accreting proto-neutron star with the hyperonic EOS stops much earlier than the corresponding case with a nucleonic EOS while the average energies and luminosities are quite similar between them. These features of neutrino signal are a potential probe of the emergence of new degrees of freedom inside the black hole forming collapse.Comment: 11 pages, 3 figures, accepted for publication in ApJ

Discontinuous transitions in double exchange materials

It is shown that the double exchange Hamiltonian, with weak antiferromagnetic interactions, has a rich variety of first order transitions between phases with different electronic densities and/or magnetizations. For band fillings in the range $0.3 \le x \le 0.5$, and at finite temperatures, a discontinuous transition between phases with similar electronic densities but different magnetizations takes place. This sharp transition, which is not suppressed by electrostatic effects, and survives in the presence of an applied field, is consistent with the phenomenology of the doped manganites near the transition temperature.Comment: three more variational ansatzs considere

Variational Mean Field approach to the Double Exchange Model

It has been recently shown that the double exchange Hamiltonian, with weak antiferromagnetic interactions, has a richer variety of first and second order transitions than previously anticipated, and that such transitions are consistent with the magnetic properties of manganites. Here we present a thorough discussion of the variational Mean Field approach that leads to the these results. We also show that the effect of the Berry phase turns out to be crucial to produce first order Paramagnetic-Ferromagnetic transitions near half filling with transition temperatures compatible with the experimental situation. The computation relies on two crucial facts: the use of a Mean Field ansatz that retains the complexity of a system of electrons with off-diagonal disorder, not fully taken into account by the Mean Field techniques, and the small but significant antiferromagnetic superexchange interaction between the localized spins.Comment: 13 pages, 11 postscript figures, revte

Optimality regions and fluctuations for Bernoulli last passage models

We study the sequence alignment problem and its independent version,the discrete Hammersley process with an exploration penalty. We obtain rigorous upper bounds for the number of optimality regions in both models near the soft edge.At zero penalty the independent model becomes an exactly solvable model and we identify cases for which the law of the last passage time converges to a Tracy-Widom law

Constructing majority-rule supertrees

<p>Abstract</p> <p>Background</p> <p>Supertree methods combine the phylogenetic information from multiple partially-overlapping trees into a larger phylogenetic tree called a supertree. Several supertree construction methods have been proposed to date, but most of these are not designed with any specific properties in mind. Recently, Cotton and Wilkinson proposed extensions of the majority-rule consensus tree method to the supertree setting that inherit many of the appealing properties of the former.</p> <p>Results</p> <p>We study a variant of one of Cotton and Wilkinson's methods, called majority-rule (+) supertrees. After proving that a key underlying problem for constructing majority-rule (+) supertrees is NP-hard, we develop a polynomial-size exact integer linear programming formulation of the problem. We then present a data reduction heuristic that identifies smaller subproblems that can be solved independently. While this technique is not guaranteed to produce optimal solutions, it can achieve substantial problem-size reduction. Finally, we report on a computational study of our approach on various real data sets, including the 121-taxon, 7-tree Seabirds data set of Kennedy and Page.</p> <p>Conclusions</p> <p>The results indicate that our exact method is computationally feasible for moderately large inputs. For larger inputs, our data reduction heuristic makes it feasible to tackle problems that are well beyond the range of the basic integer programming approach. Comparisons between the results obtained by our heuristic and exact solutions indicate that the heuristic produces good answers. Our results also suggest that the majority-rule (+) approach, in both its basic form and with data reduction, yields biologically meaningful phylogenies.</p

Evaluación geológica y geodinámica en la quebrada Chicón: aluvión del 17 de octubre del 2010 que afectó Urubamba-Cusco

En la quebrada Chicón del distrito de Urubamba, provincia de Urubamba, el día domingo 17 de Octubre del 2010 alrededor de las 23.35 hrs ocurrió un proceso de movimiento en masa. En el nevado Chicón (5530 msnm) el desprendimiento de un bloque de hielo (de aproximadamente 100 x 30m) provocó el rebalse de una pequeña laguna localizada a 4870 msnm. Este rebalse incrementó el caudal de un pequeño riachuelo que nace de esta laguna y la conecta con la laguna Pucacocha, a 4670 msnm. La laguna Pucacocha también rebalsó luego de superar su capacidad. Es a partir de la desembocadura de esta laguna, el que coincide con el cambio brusco de pendiente, que las aguas rebalsadas empiezan a erosionar el material morrénico, los cuales se hallan colgados en la ladera de pendiente muy alta (> 60º). La erosión de este material, por la gran cantidad de agua, originó un flujo de detritos (aluvión) que descendió por la Ladera Norte hasta la quebrada Occororuyoc donde se depositó gran parte del volumen aluviónico. Sin embargo, la parte liquida con sedimentos finos siguió su camino por la quebrada hasta alcanzar la quebrada de Chicón, donde producto de nuevas erosiones da lugar a otros aluviones menores que llegan hasta la ciudad de Urubamba donde destruyen numerosas viviendas en las localidades de Yanacona, Chichubamba y San Isidro de Chicón. En Urubamba afectó principalmente la Av. Ramón Castlla, el Jr. Arica y las calles transversales a estas, llegando incluso a una esquina de la Plaza de Armas. Este fenómeno afectó unas 300 viviendas, destruyó tierras de cultivo, y dejó más de 1,200 damnificados

The future of legume genetic data resources: Challenges, opportunities, and priorities

This paper is the product of the Legume Genomic Data Working Group,who discussed and debated topics presented here[EN] Legumes, comprising one of the largest, most diverse, and most economically important plant families, are the subject of vibrant research and development worldwide. Continued improvement of legume crops will benefit from the recent proliferation of genetic (including genomic) resources; but the diversity, scale, and complexity of these resources presents challenges to those managing and using them. A workshop held in March of 2019 addressed questions of data resources and priorities for the legumes. The workshop identified various needs and recommendations: (a) Develop strategies to effectively store, integrate, and relate genetic resources collected in different projects. (b) Leverage information collected across many legume species by standardizing data formats and ontologies, improving the state of metadata about datasets, and increasing use of the FAIR data principles. (c) Advocate for the critical role that curators exercise in integrating complex datasets into databases and adding high value metadata that enable downstream analytics and facilitate practical applications. (d) Implement standardized software and database development practices to best leverage limited developer time and expertise gained from the various legume (and other) species. (e) Develop tools and databases that can manage genetic information for the world's plant genetic resources, enabling efficient incorporation of important traits into breeding programs. (f) Centralize information on databases, tools, and training materials and establish funding streams to support training and outreachSIThis research was funded by the NSF project “Federated Plant Database Initiative for the Legumes” (1444806), and the USDA Agricultural Research Service project 5030–21000-062-00D. The USDA is an equal opportunity provider and employer. The work conducted by the U.S. Department of Energy Joint Genome Institute is supported by the Office of Science of the U.S. Department of Energy under Contract DE-AC02-05CH11