Stopword detection for streaming content

© Springer International Publishing AG, part of Springer Nature 2018. The removal of stopwords is an important preprocessing step in many natural language processing tasks, which can lead to enhanced performance and execution time. Many existing methods either rely on a predefined list of stopwords or compute word significance based on metrics such as tf-idf. The objective of our work in this paper is to identify stopwords, in an unsupervised way, for streaming textual corpora such as Twitter, which have a temporal nature. We propose to consider and model the dynamics of a word within the streaming corpus to identify the ones that are less likely to be informative or discriminative. Our work is based on the discrete wavelet transform (DWT) of word signals in order to extract two features, namely scale and energy. We show that our proposed approach is effective in identifying stopwords and improves the quality of topics in the task of topic detection

Learning heterogeneous subgraph representations for team discovery

The team discovery task is concerned with finding a group of experts from a collaboration network who would collectively cover a desirable set of skills. Most prior work for team discovery either adopt graph-based or neural mapping approaches. Graph-based approaches are computationally intractable often leading to sub-optimal team selection. Neural mapping approaches have better performance, however, are still limited as they learn individual representations for skills and experts and are often prone to overfitting given the sparsity of collaboration networks. Thus, we define the team discovery task as one of learning subgraph representations from a heterogeneous collaboration network where the subgraphs represent teams which are then used to identify relevant teams for a given set of skills. As such, our approach captures local (node interactions with each team) and global (subgraph interactions between teams) characteristics of the representation network and allows us to easily map between any homogeneous and heterogeneous subgraphs in the network to effectively discover teams. Our experiments over two real-world datasets from different domains, namely DBLP bibliographic dataset with 10,647 papers and IMDB with 4882 movies, illustrate that our approach outperforms the state-of-the-art baselines on a range of ranking and quality metrics. More specifically, in terms of ranking metrics, we are superior to the best baseline by approximately 15 % on the DBLP dataset and by approximately 20 % on the IMDB dataset. Further, our findings illustrate that our approach consistently shows a robust performance improvement over the baselines

The Effect of Resistance Training on Performance of Gross Motor Skills and Balance in Children with Spastic Cerebral Palsy

Objective: Cerebral palsy is the most common chronic motor disability in children and can have negative effect on motor functions. The purpose of this study was to investigate the effect of eight weeks resistance training on gross motor ability, balance and walking speed in a group of such children. Methods: 21 cerebral palsy boys with spastic diplegia, aged between 12 and 16 years (mean, 13.66 years), participated in this study. A pre-test, involving walking, sitting, standing and walking up stairs. They were randomly divided into an experimental and control groups. Then, the experimental group participated in 8 weeks of resistance training. &nbsp;The data was attained from a 10 meter walk test, Berg Balance Test, gross motor ability Section E, D and GMFCS tests. &nbsp;Kolmogorov-Smirnov test, sample t-test were used for analyzing the data. Results: The results showed a significant improvement in the performance of experimental group in gross motor abilities section&nbsp; E and D, balance and walking speed after 8 weeks of resistance training (P <0.05(. However, significant differences were not observed in the control group before and after the study (P <0.05). &nbsp;Conclusion: The results showed that resistance training improves gross motor ability, balance and gait in children with cerebral palsy hence, it is recommended that resistance exercise be used as a therapeutic modality for children with cerebral palsy

The preconditioning effect of different exercise training modes on middle cerebral artery occlusion induced-behavioral deficit in senescent rats

Introduction: Brain abilities decrease after brain stroke in elderly. The neuroprotective effect of exercise training has been proved in clinical trials and animal experiment. Nevertheless, it is not still clear what kind of exercise has greater protective effect. The present study aimed at investigating pre-conditioning effect of endurance, resistance, and concurrent training on learning ability, anxiety, and spatial memory in aged rats following stroke strength with middle cerebral artery occlusion. Method: We used 50 male Wistar rats (age = 24 months) that were assigned randomly in five groups; 1: sham group, 2: Control group 3: Endurance training 4: Resistance training, and 5: concurrent training. The exercise training groups received training for four weeks. Following training, middle cerebral artery occlusion was applied to induce cerebral ischemia. Using the elevated plus maze, shuttle box test, and Morris water maze, neurocognitive functions were tested in the sample rats. Results: It was found that resistance training did not affect spatial memory in the acquisition phase, while concurrent training and endurance training enhanced spatial memory in the acquisition phase. On the contrary, spatial memory was improved by resistance training in the retention phase, while concurrent and endurance exercises did not affect spatial memory in the retention phase. Passive avoidance learning ability at acquisition phase was more in resistance group compared to the endurance and concurrent training in shuttle box test, but in retention phase was similar between training groups. Unlike endurance and concurrent training, resistance training reduced anxiety in senescent rats. Conclusion: All three exercise types alleviated aversive learning and memory impairment induced by stroke in senescent rats. Notably, the resistance training showed a greater protective effect compared to the other two training methods

Neural embedding-based specificity metrics for pre-retrieval query performance prediction

© 2020 Elsevier Ltd In information retrieval, the task of query performance prediction (QPP) is concerned with determining in advance the performance of a given query within the context of a retrieval model. QPP has an important role in ensuring proper handling of queries with varying levels of difficulty. Based on the extant literature, query specificity is an important indicator of query performance and is typically estimated using corpus-specific frequency-based specificity metrics However, such metrics do not consider term semantics and inter-term associations. Our work presented in this paper distinguishes itself by proposing a host of corpus-independent specificity metrics that are based on pre-trained neural embeddings and leverage geometric relations between terms in the embedding space in order to capture the semantics of terms and their interdependencies. Specifically, we propose three classes of specificity metrics based on pre-trained neural embeddings: neighborhood-based, graph-based, and cluster-based metrics. Through two extensive and complementary sets of experiments, we show that the proposed specificity metrics (1) are suitable specificity indicators, based on the gold standards derived from knowledge hierarchies (Wikipedia category hierarchy and DMOZ taxonomy), and (2) have better or competitive performance compared to the state of the art QPP metrics, based on both TREC ad hoc collections namely Robust’04, Gov2 and ClueWeb’09 and ANTIQUE question answering collection. The proposed graph-based specificity metrics, especially those that capture a larger number of inter-term associations, proved to be the most effective in both query specificity estimation and QPP. We have also publicly released two test collections (i.e. specificity gold standards) that we built from the Wikipedia and DMOZ knowledge hierarchies

Comparison of the preconditioning effect of different exercise training modalities on myocardial ischemia-reperfusion injury.

The study of exercise preconditioning can develop strategies to prevent cardiovascular diseases and outline the efficient exercise model. However, the exercise type with the most protective effect against ischemia-reperfusion injury is unknown. In this study, we examined the effects of three kinds of exercise preconditioning on myocardial ischemia-reperfusion in adult rats and explored the possible underlying mechanisms. Male Wistar rats subjected to ten weeks of endurance, resistance, and concurrent training underwent ischemia (30 min) and reperfusion (120 min) induction. Then, infarction size, serum levels of the CK-MB, the redox status, and angiogenesis proteins (VEGF, ANGP-1, and ANGP-2) were measured in the cardiac tissue. Results showed that different exercise training modes have the same reduction effects on infarction size, but ischemia-reperfusion-induced CK-MB was lower in response to endurance training and concurrent training. Furthermore, cardiac VEGF levels increased in all three kinds of exercise preconditioning but ischemia-reperfusion-induced ANGP-1 elevated more in endurance training. The cardiac GPX activity was improved significantly through the resistance and concurrent exercise compared to the endurance exercise. In addition, all three exercise preconditioning models decreased MPO levels, and ischemia reperfusion-induced MDA was lower in endurance and resistance training. Overall, these results indicated that cardioprotection of exercise training against ischemia-reperfusion injury depends on the exercise modality. Cardioprotective effects of aerobic, resistance, and concurrent exercises are due to different mechanisms. The preconditioning effects of endurance training are mediated mainly by pervasive angiogenic responses and resistance training through oxidative stress amelioration. The preconditioning effects of concurrent training rely on both angiogenesis and oxidative stress amelioration