Variation P-Set and Its Structure

AbstractVariation P-set is put forward from attribute viewpoint, and its structure is given. Variation P-set is composed of variation interior P-set and variation outer P-set. Duality theorems between variation P-set and P-set are proposed. The properties of variation P-set are discussed, and the interior P-theorem, outer P-theorem of variation P-set and discrete interval dynamic generation theorem of the packet degree are proposed. The relations between variation P-set and P-set are analyzed, and the interior P-decomposition theorem and outer P-decomposition theorem of variation P-set are obtained. Variation P-set is a new research direction of P-set

Expression of the transcription factor regulatory factor X1 in the mouse brain

Limited information indicates that the regulatory factor X1 (RFX1), the prototype member of the transcription factor RFX family, may play a role in the central nervous system. Our recent study showed that knockout of the Rfx1 gene led to early embryonic death. In the present study, we showed that heterozygous Rfx1+/– mice were fertile and grew normally. An abundant amount of RFX1 proteins were expressed in the olfactory bulb, hippocampus and cerebral cortex as detected by b-galactosidase staining (the gene knockout vector contained a coding region for b-galactosidase) and immunofluorescent staining with an anti-RFX1 antibody. RFX1 positive immunostaining was mainly in the nuclei of neurons and microglial cells and was absent from the astrocytes of mouse brains. The heterozygous Rfx1+/– mice expressed RFX1 mRNA and proteins at a level similar to that in the wild-type mice in the olfactory bulb and hippocampus. The expression level of RFX1 proteins was similar in the brains of mice ranging from 15 day old embryos to four month old adults. Our results suggest a significant expression of RFX1 proteins in the mammalian brain. This expression is cell-type and brain-region specific and may take a random monoallelic expression pattern. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 2, pp. 344–351

The effect of combustion sub-grid closures in LES of MILD combustion

info:eu-repo/semantics/nonPublishe

Sub-grid models for Large Eddy Simulation of non-conventional combustion regimes

Novel combustion technologies ensuring low emissions, high efficiency and fuel flexibility are essential to meet the future challenges associated to air pollution, climate change and energy source shortage, as well as to cope with the increasingly stricter environmental regulation. Among them, Moderate or Intense Low oxygen Dilution (MILD) combustion has recently drawn increasing attention. MILD combustion is achieved through the recirculation of flue gases within the reaction region, with the effect of diluting the reactant streams. As a result, the reactivity of the system is reduced, a more uniform reaction zone is obtained, thus leading to decreased NO x and soot emissions. As a consequence of the dilution and enhanced mixing, the ratio between the mixing and chemical time scale is strongly reduced in MILD combustion, indicating the existence of very strong interactions between chemistry and fluid dynamics. In such a context, the use of combustion models that can accurately account for turbulent mixing and detailed chemical kinetics becomes mandatory. Combustion models for conventional flames usually rely on the assumption of time-scale separation (i.e., flamelets and related models), which constrain the thermochemical space accessible in the numerical simulation. Whilst the use of transported PDF methods appears still computationally prohibitive, especially for practical combustion systems, there are a number of closures showing promise for the inclusion of detailed kinetic mechanisms with affordable computational cost. They include the Partially Stirred Reactor (PaSR) approach and the Eddy Dissipation Concept (EDC) model. In order to assess these models under non-conventional MILD combustion conditions, several prototype burners were selected. They include the Adelaide and Delft jet-in-hot-coflow (JHC) burners, and the Cabra lifted flames in vitiated coflow. Both Reynolds Averaged Navier Stokes (RANS) and Large Eddy Simulations (LES) were carried out on these burners under various operating conditions and with different fuels. The results indicate the need to explicitly account for both the mixing and chemical time scales in the combustion model formulation. The generalised models developed currently show excellent predictive capabilities when compared with the available, high-fidelity experimental data, especially in their LES formulations. The advanced approaches for the evaluation of the mixing and chemical time scale were compared to several conventional estimation methods, showing their superior performances and wider range of applications. Moreover, the PaSR approach was compared with the steady Flamelet Progress Variable (FPV) model on predicting the lifted Cabra flame, proving that the unsteady behaviours associated to flame extinction and re-ignition should be appropriately considered for such kind of flame. Because of the distributed reaction area, the reacting structures in MILD combustion can be potentially resolved on a Large Eddy Simulation (LES) grid. To investigate that, a comparative study benchmarking the LES predictions for the JHC burner obtained with the PaSR closure and two implicit combustion models was carried out, with the implicit models having filtered source terms coming directly from the Arrhenius expression. The results showed that the implicit models are very similar with the conventional PaSR model on predicting the flame properties, for what concerns the mean and root-mean-square of the temperature and species mass fraction fields. To alleviate the cost associated to the use of large kinetic mechanisms, chemistry reduction and tabulation methods to dynamically reduce their size were tested and benchmarked, allowing to allocate the computational resources only where needed. Finally, advanced post-processing tools based on the theory of Computational Singular Perturbation (CSP) were employed to improve the current understanding of flame-turbulence interactions under MILD conditions, confirming the important role of both autoignition and self propagation in these flames

A golden carnival in the golden era?

This article is by LSE MSc student Zhiyi Li Earlier this month, the UK had the first state visit by a Chinese President in ten years. Xi Jinping or “Big Daddy Xi”met UK royals and politicians, visiting universities and enterprises, even enjoying fish and chips in a pub. Both British media and Chinese media gave huge coverage to the event and mass media, online news sites, together with social media, constructed a carnival-like media event with space for both humour and more serious themes

Extrinsic Factors Affecting the Accuracy of Biomedical NER

Biomedical named entity recognition (NER) is a critial task that aims to identify structured information in clinical text, which is often replete with complex, technical terms and a high degree of variability. Accurate and reliable NER can facilitate the extraction and analysis of important biomedical information, which can be used to improve downstream applications including the healthcare system. However, NER in the biomedical domain is challenging due to limited data availability, as the high expertise, time, and expenses are required to annotate its data. In this paper, by using the limited data, we explore various extrinsic factors including the corpus annotation scheme, data augmentation techniques, semi-supervised learning and Brill transformation, to improve the performance of a NER model on a clinical text dataset (i2b2 2012, \citet{sun-rumshisky-uzuner:2013}). Our experiments demonstrate that these approaches can significantly improve the model's F1 score from original 73.74 to 77.55. Our findings suggest that considering different extrinsic factors and combining these techniques is a promising approach for improving NER performance in the biomedical domain where the size of data is limited

Geometric properties of the complete-graph Ising model in the loop representation

The exact solution of the Ising model on the complete graph (CG) provides an important, though mean-field, insight for the theory of continuous phase transitions. Besides the original spin, the Ising model can be formulated in the Fortuin-Kasteleyn random-cluster and the loop representation, in which many geometric quantities have no correspondence in the spin representations. Using a lifted-worm irreversible algorithm, we study the CG-Ising model in the loop representation, and, based on theoretical and numerical analyses, obtain a number of exact results including volume fractal dimensions and scaling forms. Moreover, by combining with the Loop-Cluster algorithm, we demonstrate how the loop representation can provide an intuitive understanding to the recently observed rich geometric phenomena in the random-cluster representation, including the emergence of two configuration sectors, two length scales and two scaling windows.Comment: 10 pages, 10 figure

DCA: Diversified Co-Attention towards Informative Live Video Commenting

We focus on the task of Automatic Live Video Commenting (ALVC), which aims to generate real-time video comments with both video frames and other viewers' comments as inputs. A major challenge in this task is how to properly leverage the rich and diverse information carried by video and text. In this paper, we aim to collect diversified information from video and text for informative comment generation. To achieve this, we propose a Diversified Co-Attention (DCA) model for this task. Our model builds bidirectional interactions between video frames and surrounding comments from multiple perspectives via metric learning, to collect a diversified and informative context for comment generation. We also propose an effective parameter orthogonalization technique to avoid excessive overlap of information learned from different perspectives. Results show that our approach outperforms existing methods in the ALVC task, achieving new state-of-the-art results