5,646 research outputs found

    Zero-thickness interface model with chemical degradation by acid attack

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    Carbon dioxide (CO2) storage in abandoned oil/gas reservoirs is considered a viable alternative to reduce greenhouse gas emissions to the atmosphere. An important element of the risk associated with long-term CO2 storage is the loss of integrity of the cement seals of the abandoned wells in the reservoir. Among others, one possible cause of loss of integrity is the degradation of the oil-well cement due to the acid attack of the carbonated brine in the reservoir. In previous studies, the authors have developed a diffusion-reaction model for simulating this degradation process. In order to study possible coupled Chemo-Mechanical (CM) mechanisms, this model will be coupled with an existing mechanical model. For this purpose, in this paper, an existing constitutive law for zero-thickness interface, based on the theory of elasto-plasticity with concepts of fracture mechanics, is modified to incorporate the effect of chemical degradation on the mechanical strength parameters. Preliminary results obtained with this new constitutive law are presented, in order to illustrate the main aspects of the proposed constitutive law, as well as a possible C-M degradation mechanism that should be considered in the long-term safety assessment of CO2 geological storage projects

    Next-to-eikonal corrections in the CGC: gluon production and spin asymmetries in pA collisions

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    We present a new method to systematically include corrections to the eikonal approximation in the background field formalism. Specifically, we calculate the subleading, power-suppressed corrections due to the finite width of the target or the finite energy of the projectile. Such power-suppressed corrections involve Wilson lines decorated by gradients of the background field - thus related to the density - of the target. The method is of generic applicability. As a first example, we study single inclusive gluon production in pA collisions, and various related spin asymmetries, beyond the eikonal accuracy.Comment: 34 pages, new reference added, some typos correcte

    Medium-induced soft gluon radiation in DIS

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    We study color coherence effects on the medium-induced soft gluon radiation off an asymptotic quark hit by a virtual photon traversing a hot and dense QCD medium. The transverse momentum spectrum of the emitted gluon is computed at 1st order in the opacity expansion. The interference effects between the initial and final state radiation modify the soft gluon spectrum when a finite angle between the incoming and outgoing quarks is considered, presenting a soft divergence. We comment on possible implications on observables in eA collisions.Comment: 4 pages, 2 figure, Proceedings of DIS 2012, Bonn, German

    TBL1 is required for the mesenchymal phenotype of transformed breast cancer cells

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    The epithelial-to-mesenchymal transition (EMT) and its reversion (MET) are related to tumor cell dissemination and migration, tumor circulating cell generation, cancer stem cells, chemoresistance, and metastasis formation. To identify chromatin and epigenetic factors possibly involved in the process of EMT, we compare the levels of expression of epigenetic genes in a transformed human breast epithelial cell line (HMEC-RAS) versus a stable clone of the same cell line expressing the EMT master regulator ZEB1 (HMEC-RAS-ZEB1). One of the factors strongly induced in the HMEC-RAS-ZEB1 cells was Transducin beta-like 1 (TBL1), a component of the NCoR complex, which has both corepressor and coactivator activities. We show that TBL1 interacts with ZEB1 and that both factors cooperate to repress the promoter of the epithelial gene E-cadherin (CDH1) and to autoactivate the ZEB1 promoter. Consistent with its central role, TBL1 is required for mesenchymal phenotypes of transformed breast epithelial and breast cancer cell lines of the claudin-low subtype. Importantly, a high expression of the TBL1 gene correlates with poor prognosis and increased proportion of metastasis in breast cancer patients, indicating that the level of TBL1 expression can be used as a prognostic marker.Ministerio de Economía y Competitividad BFU2014-53543-P, BFU2017-85420-RJunta de Andalucía BIO-32

    Electricity contract price prediction using genetic programming with functional blocks

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    The prediction of the prices of the contracts in non-regulated electricenergy markets is the key for the market agents to make strategic business and operational decisions. The average prices of the contracts sold in the Colombian electric energy market are predicted in this study by means of a modified genetic programming algorithm. The developed model is capable of capturing the intrinsic dynamics of the prices and the price predictions for the upcoming months with a more accurate precision than the ARIMA and DAN2 models for prediction horizons of 12 and 14 months, as they have been reported in the literature.La predicción de los precios de los contratos en los mercados energéticos desregularizados es la clave para la toma de decisiones estratégicas de negocio y operativas por los agentes del mercado. En este trabajo se predicen los precios promedio de los contratos vendidos en el mercado eléctrico colombiano, utilizando un algoritmo de programación genética modificado. El modelo desarrollado es capaz de capturar la dinámica intrínseca de los precios y las predicciones de precios para los próximos meses con mayor precisión que los modelos ARIMA y DAN2 para horizontes de predicción de 12 y 24 meses, reportados en la literatura

    Influence of bone definition and finite element parameters in bone and dental implants stress: A literature review

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    This article belongs to the Special Issue New Trends in Bioengineering in Osseointegration and Dental Implants.Bone plays an important role in dental implant treatment success. The goal of this literature review is to analyze the influence of bone definition and finite element parameters on stress in dental implants and bone in numerical studies. A search was conducted of Pubmed, Science Direct and LILACS, and two independent reviewers performed the data extraction. The quality of the selected studies was assessed using the Cochrane Handbook tool for clinical trials. Seventeen studies were included. Titanium was the most commonly-used material in dental implants. The magnitude of the applied loads varied from 15 to 300 N with a mean of 182 N. Complete osseointegration was the most common boundary condition. Evidence from this review suggests that bone is commonly defined as an isotropic material, despite being an anisotropic tissue, and that it is analyzed as a ductile material, instead of as a fragile material. In addition, and in view of the data analyzed in this review, it can be concluded that there is no standardization for conducting finite element studies in the field of dentistry. Convergence criteria are only detailed in two of the studies included in this review, although they are a key factor in obtaining accurate results in numerical studies. It is therefore necessary to implement a methodology that indicates which parameters a numerical simulation must include, as well as how the results should be analyzed

    Complex Hybrid Inflation and Baryogenesis

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    We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U(1) global symmetry associated to the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vev of the waterfall field, which is well constrained by diverse cosmological observations.Comment: 4 RevTex pages, no figures. Changes made in response to referee's comments; matches version published in Phys.Rev.Let

    Using collocation segmentation to augment the phrase table

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    This paper describes the 2010 phrase-based statistical machine translation system developed at the TALP Research Center of the UPC1 in cooperation with BMIC2 and VMU3. In phrase-based SMT, the phrase table is the main tool in translation. It is created extracting phrases from an aligned parallel corpus and then computing translation model scores with them. Performing a collocation segmentation over the source and target corpus before the alignment causes that di erent and larger phrases are extracted from the same original documents. We performed this segmentation and used the union of this phrase set with the phrase set extracted from the nonsegmented corpus to compute the phrase table. We present the con gurations considered and also report results obtained with internal and o cial test sets.Postprint (published version

    Energy Efficiency of Hybrid-Power HetNets: A Population-like Games Approach

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    In this paper, a distributed control scheme based on population games is proposed. The controller is in charge of dealing with the energy consumption problem in a Heterogeneous Cellular Network (HetNet) powered by hybrid energy sources (grid and renewable energy) while guaranteeing appropriate quality of service (QoS) level at the same time. Unlike the conventional approach in population games, it considers both atomicity and non-anonymity. Simulation results show that the proposed population-games approach reduces grid consumption by up to about 12% compared to the traditional best-signal level association policy.U.S. Air Force Office of Scientific Research FA9550-17-1-0259Ministerio de Cultura y Deporte DPI2016-76493-C3-3-RMinisterio de Economía y Empresa DPI2017-86918-
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