100 research outputs found
Hamiltonian-Driven Adaptive Dynamic Programming with Efficient Experience Replay
This article presents a novel efficient experience-replay-based adaptive dynamic programming (ADP) for the optimal control problem of a class of nonlinear dynamical systems within the Hamiltonian-driven framework. The quasi-Hamiltonian is presented for the policy evaluation problem with an admissible policy. With the quasi-Hamiltonian, a novel composite critic learning mechanism is developed to combine the instantaneous data with the historical data. In addition, the pseudo-Hamiltonian is defined to deal with the performance optimization problem. Based on the pseudo-Hamiltonian, the conventional Hamilton–Jacobi–Bellman (HJB) equation can be represented in a filtered form, which can be implemented online. Theoretical analysis is investigated in terms of the convergence of the adaptive critic design and the stability of the closed-loop systems, where parameter convergence can be achieved under a weakened excitation condition. Simulation studies are investigated to verify the efficacy of the presented design scheme
Preparation of Nb3Al superconductor by powder metallurgy and effect of mechanical alloying on the phase formation
The Efficacy of Guanxinning Injection in Treating Angina Pectoris: Systematic Review and Meta-Analysis of Randomized Controlled Trials
Objective. The randomized controlled trials (RCTs) on Guanxinning injection (GXN) in treating angina pectoris were published only in Chinese and have not been systematically reviewed. This study aims to provide a PRISMA-compliant and internationally accessible systematic review to evaluate the efficacy of GXN in treating angina pectoris. Methods. The RCTs were included according to prespecified eligibility criteria. Meta-analysis was performed to evaluate the symptomatic (SYMPTOMS) and electrocardiographic (ECG) improvements after treatment. Odds ratios (ORs) were used to measure effect sizes. Subgroup analysis, sensitivity analysis, and metaregression were conducted to evaluate the robustness of the results. Results. Sixty-five RCTs published between 2002 and 2012 with 6064 participants were included. Overall ORs comparing GXN with other drugs were 3.32 (95% CI: [2.72, 4.04]) in SYMPTOMS and 2.59 (95% CI: [2.14, 3.15]) in ECG. Subgroup analysis, sensitivity analysis, and metaregression found no statistically significant dependence of overall ORs upon specific study characteristics. Conclusion. This meta-analysis of eligible RCTs provides evidence that GXN is effective in treating angina pectoris. This evidence warrants further RCTs of higher quality, longer follow-up periods, larger sample sizes, and multicentres/multicountries for more extensive subgroup, sensitivity, and metaregression analyses
Genome Sequence and Transcriptome Analysis of the Radioresistant Bacterium Deinococcus gobiensis: Insights into the Extreme Environmental Adaptations
The desert is an excellent model for studying evolution under extreme environments. We present here the complete genome and ultraviolet (UV) radiation-induced transcriptome of Deinococcus gobiensis I-0, which was isolated from the cold Gobi desert and shows higher tolerance to gamma radiation and UV light than all other known microorganisms. Nearly half of the genes in the genome encode proteins of unknown function, suggesting that the extreme resistance phenotype may be attributed to unknown genes and pathways. D. gobiensis also contains a surprisingly large number of horizontally acquired genes and predicted mobile elements of different classes, which is indicative of adaptation to extreme environments through genomic plasticity. High-resolution RNA-Seq transcriptome analyses indicated that 30 regulatory proteins, including several well-known regulators and uncharacterized protein kinases, and 13 noncoding RNAs were induced immediately after UV irradiation. Particularly interesting is the UV irradiation induction of the phrB and recB genes involved in photoreactivation and recombinational repair, respectively. These proteins likely include key players in the immediate global transcriptional response to UV irradiation. Our results help to explain the exceptional ability of D. gobiensis to withstand environmental extremes of the Gobi desert, and highlight the metabolic features of this organism that have biotechnological potential
Interrogation of the perturbed gut microbiota in gouty arthritis patients through in silico metabolic modeling
Recent studies have shown perturbed gut microbiota associated with gouty arthritis, a metabolic disease characterized by an imbalance between uric acid production and excretion. To mechanistically investigate altered microbiota metabolism associated with gout disease, 16S rRNA gene amplicon sequence data from stool samples of gout patients and healthy controls were computationally analyzed through bacterial community metabolic models. Patient-specific community models constructed with the metagenomics modeling pipeline, mgPipe, were used to perform k-means clustering of samples according to their metabolic capabilities. The clustering analysis generated statistically significant partitioning of samples into a Bacteroides-dominated, high gout cluster and a Faecalibacterium-elevated, low gout cluster. The high gout cluster was predicted to allow elevated synthesis of the amino acids D-alanine and L-alanine and byproducts of branched-chain amino acid catabolism, while the low gout cluster allowed higher production of butyrate, the sulfur-containing amino acids L-cysteine and L-methionine, and the L-cysteine catabolic product H2S. By expanding the capabilities of mgPipe to provide taxa-level resolution of metabolite exchange rates, acetate, D-lactate and succinate exchanged from Bacteroides to Faecalibacterium were predicted to enhance butyrate production in the low gout cluster. Model predictions suggested that sulfur-containing amino acid metabolism generally and H2S more specifically could be novel gout disease markers
IrrE, a Global Regulator of Extreme Radiation Resistance in Deinococcus radiodurans, Enhances Salt Tolerance in Escherichia coli and Brassica napus
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
A Critical Analysis of Theoretical Concepts, Jim Cummins, Bristol, UK; Blue Ridge Summit, PA: Multilingual Matters, (2021), 464 pages, ISBN-13: 978-1-80041-357-3
Multilingualism has always been a pervasive phenomenon in the academic arena and societies, where people belonging to dissimilar linguistic and cultural backgrounds live and/or study beside the mainstream group (Gorter & Arocena, 2020). The issue gained more momentum with the globalization of English and the internationalization of education that led to an exponential rate of immigration and juxtaposition of native and non-native students at schools (Walker, 2018). Given the significance of multilingual education, a growing body of research has been conducted to unpack its multiple dimensions (Sun & Zhang, 2020). Although such studies have offered promising insights, this strand of research still demands more scholarly attention devoted to the understanding of theories, policies, and practices of multilingualism to help students learn English and succeed in academia. To make this happen and bridge the gaps, Jim Cummins’ monograph, entitled “Rethinking the Education of Multilingual Learners: A Critical Analysis of Theoretical Concepts”, presents the readers with a personal journey that covers more than 40 years of research and practice in bilingualism and multilingualism.Multilingualism has always been a pervasive phenomenon in the academic arena and societies, where people belonging to dissimilar linguistic and cultural backgrounds live and/or study beside the mainstream group (Gorter & Arocena, 2020). The issue gained more momentum with the globalization of English and the internationalization of education that led to an exponential rate of immigration and juxtaposition of native and non-native students at schools (Walker, 2018). Given the significance of multilingual education, a growing body of research has been conducted to unpack its multiple dimensions (Sun & Zhang, 2020). Although such studies have offered promising insights, this strand of research still demands more scholarly attention devoted to the understanding of theories, policies, and practices of multilingualism to help students learn English and succeed in academia. To make this happen and bridge the gaps, Jim Cummins’ monograph, entitled “Rethinking the Education of Multilingual Learners: A Critical Analysis of Theoretical Concepts”, presents the readers with a personal journey that covers more than 40 years of research and practice in bilingualism and multilingualism
Immunoglobulin Replacement Therapy for Hypogammaglobulinemia in Multiple Myeloma Should Not Be Ignored
- …