Primary Channel Gain Estimation for Spectrum Sharing in Cognitive Radio Networks

In cognitive radio networks, the channel gain between primary transceivers, namely, primary channel gain, is crucial for a cognitive transmitter (CT) to control the transmit power and achieve spectrum sharing. Conventionally, the primary channel gain is estimated in the primary system and thus unavailable at the CT. To deal with this issue, two estimators are proposed by enabling the CT to sense primary signals. In particular, by adopting the maximum likelihood (ML) criterion to analyze the received primary signals, a ML estimator is first developed. After demonstrating the high computational complexity of the ML estimator, a median based (MB) estimator with proved low complexity is then proposed. Furthermore, the estimation accuracy of the MB estimation is theoretically characterized. By comparing the ML estimator and the MB estimator from the aspects of the computational complexity as well as the estimation accuracy, both advantages and disadvantages of two estimators are revealed. Numerical results show that the estimation errors of the ML estimator and the MB estimator can be as small as $0.6$ dB and $0.7$ dB, respectively.Comment: Submitted to IEEE Transactions on Communication

Modeling Viscoelastomers With Nonlinear Viscosity

Consisting of highly mobile and flexible polymer chains, elastomers are known to exhibit viscoelastic behavior. Adopting concepts from the theory of polymer dynamics and finite-deformation viscoelasticity, this work presents a micromacro constitutive model to investigate the viscoelastic behavior of elastomers, in which the material viscosity varies with the macroscopic deformation. The developed model is then applied to study the stress response of elastomers. From the simulation results, it is observed that the developed model exhibits strong capability of capturing the typical response behaviors of elastomers (e.g., strain-softening behavior). A comparison of the stress responses between linear and nonlinear viscosity is also considered in this work. The modeling framework in this paper is expected to provide a general approach and a platform to analyze the viscoelastic behavior of rubber-like materials with nonlinear viscosity

Genetic diversity of five goat breeds in China based on microsatellite markers

The genetic diversity of five goat breeds in China was surveyed using 15 microsatellites. The five goat breeds included Tangshan dairy goat (TSD), Liaoning cashmere goat (LNC), Nanjiang yellow goat (NJY), Chengde  polled goat (CDP) and Leizhou black goat (LZB). The mean polymorphism information content value (PIC) of  the populations ranged from 0.6606 to 0.8405. The mean heterozygosity (H) of the populations ranged from  0.7936 to 0.8202. The mean number of effective allele (Ne) of the populations ranged from 5.3373 to 5.8812 and the coefficient of genetic differentiation between breeds was 0.0620. It was suggested that the five goat  populations have abundant genetic diversity and extensive genetic basis, with limited inbreeding, especially in Leizhou black goat. The unweighted pair-group method with arithmetic averages (UPGMA) dendrogram based  on the Nei's standard genetic distance indicated that Tangshan dairy goat, Chengde polled goat and Liaoning  cashmere goat breeds / populations clustered together. The Nanjiang yellow goat and Leizhou black goat  populations clustered together, consistent with the geographical distribution of goat breeds.Key words: Goat, microsatellite, genetic diversity, clustering

Paraoxon Attenuates Vascular Smooth Muscle Contraction through Inhibiting Ca2+ Influx in the Rabbit Thoracic Aorta

We investigated the effect of paraoxon on vascular contractility using organ baths in thoracic aortic rings of rabbits and examined the effect of paraoxon on calcium homeostasis using a whole-cell patch-clamp technique in isolated aortic smooth muscle cells of rabbits. The findings show that administration of paraoxon (30 μM) attenuated thoracic aorta contraction induced by phenylephrine (1 μM) and/or a high K+ environment (80 mM) in both the presence and absence of thoracic aortic endothelium. This inhibitory effect of paraoxon on vasoconstrictor-induced contraction was abolished in the absence of extracellular Ca2+, or in the presence of the Ca2+ channel inhibitor, verapamil. But atropine had little effect on the inhibitory effect of paraoxon on phenylephrine-induced contraction. Paraoxon also attenuated vascular smooth muscle contraction induced by the cumulative addition of CaCl2 and attenuated an increase of intracellular Ca2+ concentration induced by K+ in vascular smooth muscle cells. Moreover, paraoxon (30 μM) inhibited significantly L-type calcium current in isolated aortic smooth muscle cells of rabbits. In conclusion, our results demonstrate that paraoxon attenuates vasoconstrictor-induced contraction through inhibiting Ca2+ influx in the rabbits thoracic aorta

Optimization of urban distribution centres: a multi-stage dynamic location approach

Customer demand is dynamic and changeable; thus, optimality of the enterprise’s initial location cannot be guaranteed throughout the planning period in order to minimize site selection cost and maximize service reliability in the whole operation cycle. The enterprise planning period is divided into different stages, and a static location model is established at the fixed stage. In addition, a multi-stage dynamic location model is established by introducing the transfer cost between adjacent stages. To reduce the difficulty of solving the dynamic location model, first, we determined the optimal site selection and allocation strategy for each stage. Second, we designed a novel method that transforms the multi-stage dynamic location problem into the shortest path problem in graph theory. Finally, the Dijkstra algorithm was used to find the optimal dynamic location sequence so that its cumulative cost was the lowest in the whole planning period. Through a case study in China, we compare the costs of static and dynamic locations and the location cost under different objectives. The results show that this dynamic location generates more income (as it reduces cost) in comparison to the previous static location, and different location objectives have a substantial influence on location results. At the same time, the findings indicate that exploring the problem of enterprise location from a dynamic perspective could help reduce the operating cost and resources from a sustainable development perspective.Postprint (published version

Abusive Supervision, Leader-Member Exchange, and Creativity: A Multilevel Examination

Despite the growing attention on the topic of abusive supervision, how abusive supervision affects individual and team creativity have not yet been thoroughly investigated. Drawn from the perspective of leader-member exchange (LMX), the current study develops a multilevel model to describe the relationships between abusive supervision and creativity at both team and individual levels, with a focus on the roles played by team-level leader-member exchange (TLMX) and LMX differentiation (DLMX). Based on data collected from 319 team members and their team leaders in 71 teams, the results show that abusive supervision has a negative relationship with TLMX, a practice that is conducive to both team and individual creativity. At the team level, the negative relationship between abusive supervision and TLMX is lessened by a higher level of DLMX. In addition, the positive relationship between TLMX and team creativity is weakened by a higher level of DLMX. Theoretical and practical implications of the findings are discussed

MReD: A Meta-Review Dataset for Structure-Controllable Text Generation

When directly using existing text generation datasets for controllable generation, we are facing the problem of not having the domain knowledge and thus the aspects that could be controlled are limited. A typical example is when using CNN/Daily Mail dataset for controllable text summarization, there is no guided information on the emphasis of summary sentences. A more useful text generator should leverage both the input text and the control signal to guide the generation, which can only be built with a deep understanding of the domain knowledge. Motivated by this vision, our paper introduces a new text generation dataset, named MReD. Our new dataset consists of 7,089 meta-reviews and all its 45k meta-review sentences are manually annotated with one of the 9 carefully defined categories, including abstract, strength, decision, etc. We present experimental results on start-of-the-art summarization models, and propose methods for structure-controlled generation with both extractive and abstractive models using our annotated data. By exploring various settings and analyzing the model behavior with respect to the control signal, we demonstrate the challenges of our proposed task and the values of our dataset MReD. Meanwhile, MReD also allows us to have a better understanding of the meta-review domain.Comment: 15 pages, 5 figures, accepted at ACL 202

Tuning the Magnetic Ordering Temperature of Hexagonal Ferrites by Structural Distortion Control

To tune the magnetic properties of hexagonal ferrites, a family of magnetoelectric multiferroic materials, by atomic-scale structural engineering, we studied the effect of structural distortion on the magnetic ordering temperature (TN). Using the symmetry analysis, we show that unlike most antiferromagnetic rare-earth transition-metal perovskites, a larger structural distortion leads to a higher TN in hexagonal ferrites and manganites, because the K3 structural distortion induces the three-dimensional magnetic ordering, which is forbidden in the undistorted structure by symmetry. We also revealed a near-linear relation between TN and the tolerance factor and a power-law relation between TN and the K3 distortion amplitude. Following the analysis, a record-high TN (185 K) among hexagonal ferrites was predicted in hexagonal ScFeO3 and experimentally verified in epitaxially stabilized films. These results add to the paradigm of spin-lattice coupling in antiferromagnetic oxides and suggests further tunability of hexagonal ferrites if more lattice distortion can be achieved

S-adenosyl-L-methionine improves ventricular remodeling after myocardial infarction by regulating angiogenesis and fibrosis

Purpose: To investigate the effect of S-adenosyl-L-methionine (SAM) on angiogenesis and fibrosis in the heart of rats with myocardial infarction (MI), and to determine the mechanism of action.Methods: Sprague Dawley rats with MI received SAM treatment (15 mg/kg) intraperitoneally. The cumulative survival (%) of rats was recorded to determine their rate of survival. Hematoxylin-eosin staining, echocardiography, and hemodynamics were also performed. In addition, the effects of SAM vascular regeneration in the rats were analyzed by determining the expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and hypoxia-inducible factor 1-α (HIF1-α) in rats.Results: The 8-week survival rate of the MI group was significantly lower than that of the sham group, while SAM significantly improved the survival rate of the rats. In addition, SAM improved the contractile and diastolic heart function in the rats and also increased the ventricular pressure change. Furthermore, SAM elevated the expressions of VEGF, bFGF and HIF1-α in rat myocardium and serum. In myocardial tissues of SAM-treated rats, the expressions of collagen I, collagen III and α-sma were reduced, indicating that SAM inhibited myocardial fibrosis. In addition, SAM promoted cardiac angiogenesis by activating Jagged1/Notch1 signaling pathway.Conclusion: SAM promotes angiogenesis of the myocardium by activating Jagged1/Notch1 signaling pathway and inhibiting fibrosis in rat myocardium. Therefore, SAM effectively inhibits ventricular remodeling in rats after MI, thereby improving the rats’ heart structure and function. The results may provide new targets for the treatment of myocardial infarction

Resistance practice on Chinese social media:Shifting to the “second half” of COVID-19 era

Previous studies on examining resistance practice online in China focus on the netizens’ response to breaking incidents and its potentials of challenging political power negotiation within social media sphere. This study explores the shifting effect on the strategic resistance practice in anaphase of COVID-19 pandemic, in which Chinese netizens shaped a unique combination of strategy-making and purposes under the persistent anti-pandemic policy, the ever-evolving censorship and the distraction released by government. Based on a qualitative discourse analysis of 2456 Weibo comments under three trending and distractive topics in April 2022, this study adopts the discursive pragmatic approach to reveal the major strategies utilised by netizens and their purposes of resistance in context. Within the current discourse, parody, teasing, and constructed utterances were identified as the major strategies, while a comparison with general Chinese online discourse shows that neology (novel words/expressions or existing words/expressions with new meanings) was dynamically and imaginatively applied by netizens for resistance. Further content analysis demonstrates that these strategies were served for combining personal experience, eye witnessing, sentiments and adaptations of latest memes with resistance as well as evasion of censorship, during which netizens with pragmatic competence of others’ outputs and the shared social-cultural background knowledge regarding pandemic events can achieve interactive and communicative exchange. Compared to existing Chinese social media discourse research literature during pandemic, this study exemplifies Chinese netizens shifted themselves from the cyber nationalism campaign during the “first half” to the “second half” of pandemic by rejecting deliberate distraction, focusing on their “mundane desires,” and showing little interests in leading collective political events online in everyday life with long-term anti-pandemic measures and up-to-date Internet surveillance. This shifting effect also enriches the description of liminal space in which the delay between netizen’s response, government supervision and censorship update under pandemic settings is different from the one shown in public incidents