70 research outputs found

    An Inequality for Ratios of Gamma Functions

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    An inequality concerning ratios of gamma functions is proved. This answers a question of Guo and Qi (2003)

    Black-box Generalization of Machine Teaching

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    Hypothesis-pruning maximizes the hypothesis updates for active learning to find those desired unlabeled data. An inherent assumption is that this learning manner can derive those updates into the optimal hypothesis. However, its convergence may not be guaranteed well if those incremental updates are negative and disordered. In this paper, we introduce a black-box teaching hypothesis hTh^\mathcal{T} employing a tighter slack term (1+FT(h^t))Δt\left(1+\mathcal{F}^{\mathcal{T}}(\widehat{h}_t)\right)\Delta_t to replace the typical 2Δt2\Delta_t for pruning. Theoretically, we prove that, under the guidance of this teaching hypothesis, the learner can converge into a tighter generalization error and label complexity bound than those non-educated learners who do not receive any guidance from a teacher:1) the generalization error upper bound can be reduced from R(h)+4ΔT1R(h^*)+4\Delta_{T-1} to approximately R(hT)+2ΔT1R(h^{\mathcal{T}})+2\Delta_{T-1}, and 2) the label complexity upper bound can be decreased from 4θ(TR(h)+2O(T))4 \theta\left(TR(h^{*})+2O(\sqrt{T})\right) to approximately 2θ(2TR(hT)+3O(T))2\theta\left(2TR(h^{\mathcal{T}})+3 O(\sqrt{T})\right). To be strict with our assumption, self-improvement of teaching is firstly proposed when hTh^\mathcal{T} loosely approximates hh^*. Against learning, we further consider two teaching scenarios: teaching a white-box and black-box learner. Experiments verify this idea and show better generalization performance than the fundamental active learning strategies, such as IWAL, IWAL-D, etc

    DNN-Based ADNMPC of an Industrial Pickling Cold-Rolled Titanium Process via Field Enhancement Heat Exchange

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    The dynamic neural network based adaptive direct nonlinear model predictive control is designed to control an industrial microwave heating pickling cold-rolled titanium process. The identifier of the direct adaptive nonlinear model identification and the controller of the adaptive nonlinear model predictive control are designed based on series-parallel dynamic neural network training by RLS algorithm with variable incremental factor, gain, and forgetting factor. These identifier and controller are used to constitute intelligent controller for adjusting the temperature of microwave heating acid. The correctness of the controller structure, the convergence, and feasibility of the control algorithms is tested by system simulation. For a given point tracking, model mismatch simulation results show that the controller can be implemented on the system to track and overcome the mismatch system model. The control model can be achieved to track on pickling solution concentration and temperature of a given reference and overcome the disturbance

    The association between serum phosphorus and common carotid artery intima–media thickness in ischemic stroke patients

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    PurposeAn elevated concentration of phosphorus is associated with an increased risk of atherosclerosis and cardiovascular diseases. Common carotid artery intima–media thickness (cIMT) is an imaging marker of atherosclerosis. However, data on the relationship between phosphorus and cIMT in ischemic stroke are scarce. We aimed to evaluate the association between serum phosphorus levels and cIMT in patients who had experienced ischemic stroke.Patients and methodsA total of 1,450 ischemic stroke patients were enrolled. Participants were divided into four groups (quartiles) according to baseline serum phosphorus level. Carotid atherosclerosis was identified by measurement of cIMT; abnormal cIMT was defined as a maximum cIMT or mean cIMT ≥ 1 mm. Multivariable logistic regression models were used to assess the association between serum phosphorus level and the presence of abnormal cIMT.ResultsIn the multivariable adjusted analysis, falling into the highest quartile for serum phosphorus (Q4) was associated with a 2.00-fold increased risk of having abnormal maximum cIMT [adjusted odds ratio (OR) 2.00; 95% confidence interval (CI) 1.44–2.79] and a 1.76-fold increased risk of having abnormal mean cIMT (adjusted OR 1.76; 95% CI 1.22–2.53) in comparison to Q1. Furthermore, the association between serum phosphorus and abnormal cIMT was confirmed in analyses treating serum phosphorus as a continuous variable and in subgroup analyses.ConclusionIn acute ischemic stroke patients, baseline elevated serum phosphorus level was found to be independently associated with carotid atherosclerosis, as measured by cIMT

    Discovery and fine-mapping of adiposity loci using high density imputation of genome-wide association studies in individuals of African ancestry: African Ancestry Anthropometry Genetics Consortium

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    Genome-wide association studies (GWAS) have identified >300 loci associated with measures of adiposity including body mass index (BMI) and waist-to-hip ratio (adjusted for BMI, WHRadjBMI), but few have been identified through screening of the African ancestry genomes. We performed large scale meta-analyses and replications in up to 52,895 individuals for BMI and up to 23,095 individuals for WHRadjBMI from the African Ancestry Anthropometry Genetics Consortium (AAAGC) using 1000 Genomes phase 1 imputed GWAS to improve coverage of both common and low frequency variants in the low linkage disequilibrium African ancestry genomes. In the sex-combined analyses, we identified one novel locus (TCF7L2/HABP2) for WHRadjBMI and eight previously established loci at P < 5×10−8: seven for BMI, and one for WHRadjBMI in African ancestry individuals. An additional novel locus (SPRYD7/DLEU2) was identified for WHRadjBMI when combined with European GWAS. In the sex-stratified analyses, we identified three novel loci for BMI (INTS10/LPL and MLC1 in men, IRX4/IRX2 in women) and four for WHRadjBMI (SSX2IP, CASC8, PDE3B and ZDHHC1/HSD11B2 in women) in individuals of African ancestry or both African and European ancestry. For four of the novel variants, the minor allele frequency was low (<5%). In the trans-ethnic fine mapping of 47 BMI loci and 27 WHRadjBMI loci that were locus-wide significant (P < 0.05 adjusted for effective number of variants per locus) from the African ancestry sex-combined and sex-stratified analyses, 26 BMI loci and 17 WHRadjBMI loci contained ≤ 20 variants in the credible sets that jointly account for 99% posterior probability of driving the associations. The lead variants in 13 of these loci had a high probability of being causal. As compared to our previous HapMap imputed GWAS for BMI and WHRadjBMI including up to 71,412 and 27,350 African ancestry individuals, respectively, our results suggest that 1000 Genomes imputation showed modest improvement in identifying GWAS loci including low frequency variants. Trans-ethnic meta-analyses further improved fine mapping of putative causal variants in loci shared between the African and European ancestry populations

    The safety and immunogenicity to inactivated COVID-19 vaccine in patients with hyperlipemia

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    It is of urgent need to understand the safety and effectiveness of novel coronavirus (COVID-19)-inactivated vaccine in patients with hyperlipidemia (HLD). However, data on the safety and immune response of SARS-CoV-2-inactivated vaccine in HLD patients are limited. In this prospective study, 105 patients with HLD and 74 healthy controls (HCs) were selected. Within 16–168 days after inoculation-inactivated vaccine, the anti-receptor-binding domain (RBD) IgG and SARS-CoV-2 neutralizing antibodies (NAbs) were evaluated, respectively. Flow cytometry was performed to evaluate RBD-specific B cells and memory B cells. There was no significant difference between HLD patients and HCs in adverse events (AEs) within 7 days after vaccination, and no serious AEs occurred. The seropositivity rates and titers of two Abs (anti-RBD IgG and CoV-2 NAbs) were lower in HLD patients than in HCs (all, p < 0.05). HLD showed significantly lower frequencies of RBD-specific B cells than HCs (p = 0.040). However, in high cholesterol, high triglyceride, mixed (MiX), and lipid control (HC) subgroups, there was no significant difference in the seropositivity rates and titers of the both Abs. Through mixed factor analysis shows that days between the second dose and sample collection/antibody measurement were associated with the lower anti-RBD IgG antibody levels. In conclusion, inactivated COVID-19 vaccine is safe and well tolerated for HLD patients, but the humoral immune may be limited

    Dynamic System Analysis of Leadership Effectiveness in Complex Environments

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    In this paper, based on chaos theory and dynamic system simulation, a dynamic model of a relational leadership system with pressure factors is established and simulated. The study found that the excessive self-leadership and the relational leadership cannot effectively improve the leadership effectiveness of leaders. In addition, with the adjustment of the self-leadership adjustment coefficient, leadership effectiveness will change from a stable state to a chaotic state. Only by adopting limited rational decision-making strategies in multicycle decision-making can leaders maintain a high level of leadership effectiveness. Previous research mainly focuses on the theoretical analysis of the complexity of the leadership system or the issuance of questionnaires, but seldom on the dynamic complex process of the leadership system. This study reveals the complexity and chaos characteristics of the dynamic evolution of the multifactor relational leadership system, puts forward the relational leadership theory and the complex leadership theory under the influence of pressure, and makes some suggestions on how to improve the leadership effectiveness under the complex environment. The research results are of great significance to theoretical innovation and practical application

    Upgrading Development and Application of Agricultural Information Service System Based on WeChat Public Platform— —A Case of WeChat Public Platform of 12396 Beijing new rural sci-tech service hotline

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    The WeChat public platform is a new service platform based on WeChat applications that provides business services and user management for individuals, businesses and organizations. It provides a new solution to the lag of agricultural information dissem-ination in the traditional media. However, services based on Tencent's backend can only meet the basic needs of users and reduce the user's experience in agricultural science and technology consulting process. In order to provide efficient and convenient service to users and solve existing problems in consultation process, the platform-related API were used to upgrade the 12396 hotline WeChat public platform to an integrated agricultural information interactive service system. It mainly carries out the following three aspects to upgrade development. Firstly, 12396 hotline WeChat public platform added two sub-menu items, “use ask” and “expert answer” to push the user’s question to expert directly, reducing the backend customer service’s works and improving the efficiency of problem solving. Secondly, 12396 WeChat public platform upgraded and developed an integrated "one-stop" micro-site to allow users know the agriculture market timely, releasing supply and demand information, etc. Thirdly, the 12396 WeChat public platform combined initiative push information with the user's automatic acquisition of information by sending keywords which increased user selectivity. The upgraded platform has obtained a good preliminary application achievement and recognized and welcomed by users. Finally, we concluded and looked forward to the future development direction of agricultural mobile consulting
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