8,821 research outputs found
Characterization of the regulatory region of bovine mucin 2 (MUC2) gene.
Na publicação: E. O. Melo
Comparing Mixed & Integer Programming vs. Constraint Programming by solving Job-Shop Scheduling Problems
Scheduling is a key factor for operations management as well as for business success. From industrial Job-shop Scheduling problems (JSSP), many optimization challenges have emerged since de 1960s when improvements have been continuously required such as bottlenecks allocation, lead-time reductions and reducing response time to requests. With this in perspective, this work aims to discuss 3 different optimization models for minimizing Makespan. Those 3 models were applied on 17 classical problems of examples JSSP and produced different outputs. The first model resorts on Mixed and Integer Programming (MIP) and it resulted on optimizing 60% of the studied problems. The other models were based on Constraint Programming (CP) and approached the problem in two different ways: a) model CP1 is a standard IBM algorithm whereof restrictions have an interval structure that fail to solve 53% of the proposed instances, b) Model CP-2 approaches the problem with disjunctive constraints and optimized 88% of the instances. In this work, each model is individually analyzed and then compared considering: i) Optimization success performance, ii) Computational processing time, iii) Greatest Resource Utilization and, iv) Minimum Work-in-process Inventory. Results demonstrated that CP-2 presented best results on criteria i and ii, but MIP was superior on criteria iii and iv and those findings are discussed at the final section of this work
On the quark-gluon vertex and quark-ghost kernel: combining lattice simulations with Dyson-Schwinger equations
We investigate the dressed quark-gluon vertex combining two established nonperturbative approaches to QCD: the Dyson-Schwinger equation (DSE) for the quark propagator and lattice-regularized simulations for the quark, gluon and ghost propagators. The vertex is modeled using a generalized Ball-Chiu ansatz parameterized by a single form
actor X̃_0 which effectively represents the quark-ghost scattering kernel. The solution space
of the DSE inversion for X̃_0 is highly degenerate, which can be dealt with by a numerical regularization scheme. We consider two possibilities: (i) linear regularization and (ii) the Maximum Entropy Method. These two numerical approaches yield compatible X̃_0 functions for the range of momenta where lattice data is available and feature a strong enhancement of the generalized Ball-Chiu vertex for momenta below 1 GeV. Our ansatz for the quark-gluon vertex is then used to solve the quark Dyson-Schwinger equation which yields a mass function in good agreement with lattice simulations and thus provides adequate dynamical chiral symmetry breaking
Efeitos de substratos e concentrações de ácido indolilbutírico no enraizamento de estacas de Passiflora setacea L.
O presente trabalho teve por objetivo avaliar o potencial de enraizamento de estacas medianas de Passiflora setacea L
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