14,646 research outputs found

    The distinctions between Λ\LambdaCDM and f(T)f(T) gravity according Noether symmetry

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    Noether's theory offers us a useful tool to research the conserved quantities and symmetries of the modified gravity theories, among which the f(T)f(T) theory, a generally modified teleparallel gravity, has been proposed to account for the dark energy phenomena. By the Noether symmetry approach, we investigate the power-law, exponential and polynomial forms of f(T)f(T) theories. All forms of f(T)f(T) concerned in this work possess the time translational symmetry, which is related with energy condition or Hamilton constraint. In addition, we find out that the performances of the power-law and exponential forms are not pleasing. It is rational adding a linear term TT to TnT^n as the most efficient amendment to resemble the teleparallel gravity or General Relativity on small scales, ie., the scale of the solar system. The corresponding Noether symmetry indicates that only time translational symmetry remains. Through numerically calculations and observational data-sets constraining, the optimal form αT+βT−1\alpha T + \beta T^{-1} is obtained, whose cosmological solution resembles the standard Λ\LambdaCDM best with lightly reduced cosmic age which can be alleviated by introducing another TmT^m term. More important is that we find the significant differences between Λ\LambdaCDM and f(T)f(T) gravity. The Λ\LambdaCDM model has also two additional symmetries and corresponding positive conserved quantities, except the two negative conserved quantities.Comment: 9 pages, 5 figures, 2 tables, typos corrected, Refs. added, accepted by EPJ-

    Dual-view Curricular Optimal Transport for Cross-lingual Cross-modal Retrieval

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    Current research on cross-modal retrieval is mostly English-oriented, as the availability of a large number of English-oriented human-labeled vision-language corpora. In order to break the limit of non-English labeled data, cross-lingual cross-modal retrieval (CCR) has attracted increasing attention. Most CCR methods construct pseudo-parallel vision-language corpora via Machine Translation (MT) to achieve cross-lingual transfer. However, the translated sentences from MT are generally imperfect in describing the corresponding visual contents. Improperly assuming the pseudo-parallel data are correctly correlated will make the networks overfit to the noisy correspondence. Therefore, we propose Dual-view Curricular Optimal Transport (DCOT) to learn with noisy correspondence in CCR. In particular, we quantify the confidence of the sample pair correlation with optimal transport theory from both the cross-lingual and cross-modal views, and design dual-view curriculum learning to dynamically model the transportation costs according to the learning stage of the two views. Extensive experiments are conducted on two multilingual image-text datasets and one video-text dataset, and the results demonstrate the effectiveness and robustness of the proposed method. Besides, our proposed method also shows a good expansibility to cross-lingual image-text baselines and a decent generalization on out-of-domain data

    Polysaccharides isolated from Morinda officinalis How roots inhibits cyclophosphamide-induced leukopenia in mice

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    Purpose: To investigate the optimum parameters for extracting polysaccharides from Morinda officinalis How (MOP), and explore their inhibitory effects on leukopenia in mice.Methods: Orthogonal design was performed to investigate the optimum parameters for extracting MOP. A leukopenia mouse model was established by injection of cyclophosphamide (CTX) for three days. Thereafter, MOP (100, 200 and 400 mg/kg) was administered orally for 10 days. Furthermore, blood cells (leukocytes, neutrophil, lymphocyte and mononuclear cell) were analyzed, while serum IL-3 and IL- 6 were determined by ELISA. The thymus and spleen of the mice were separated and weighed to determine viscera indices.Results: Orthogonal design showed that the influence order of the four factors was extraction times (C) > ratio of water to raw material (RWM, D) > extraction time (B) > extraction temperature (A). The optimum extraction parameters for MOP were: extraction temperature (80 °C), extraction duration (2 h), no. of extractions (3), and ratio of water to raw material (30 mL/g). Furthermore, the results indicate that MOP (100, 200 and 400 mg/kg) elevated the levels of leukocyte (p < 0.01), neutrophil (p < 0.01), lymphocyte (p < 0.01) and mononuclear cell (p < 0.01) in leukopenia mice. Besides, MOP (100, 200 and 400 mg/kg) also increased thymus (p < 0.01) and spleen (p < 0.05) indices and serum levels of IL-3 (p < 0.05) and IL-6 (p < 0.01).Conclusion: Orthogonal design is a good strategy for optimizing extraction parameters of MOP. Furthermore, MOP stimulated synthesis of leukocytes in CTX-induced leukopenia in mice. Thus, MOP is a potential adjunct for the treatment of tumors/cancers.Keywords: Morinda officinalis, Polyscacharide, Orthogonal design, Leukopenia, Thymus index, Spleen inde

    The Effects of Qigong on Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

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    Objective. The purpose of this study was to investigate the effects of Qigong on type 2 diabetes mellitus (DM) using the systematic review and meta-analysis. Methods. All prospective, randomized, controlled clinical trials published in English or Chinese and involving the use of Qigong by patients with DM were searched in 7 electronic databases from their respective inception to June 2016. The meta-analysis was conducted using the Revman 5.2. The quality of the included trials was assessed using the Jadad rating scale. Two researchers independently completed the inclusion, data extraction, and quality assessment. Results. Twenty-one trials with 1326 patients met the inclusion criteria and were reviewed. The meta-analysis demonstrated that, compared with no exercise, the Qigong had significant effects on fasting blood glucose (MD = −0.99, 95% CI (−1.23, 0.75), P<0.0001), HbA1c (MD = −0.84, 95% CI (−1.02, −0.65), P<0.0001), and postprandial blood glucose (MD = −1.55, 95% CI (−2.19, −0.91), P<0.00001). Conclusion. The Qigong training can improve the blood glucose status of the type 2 DM patients and has positive effects on the management of type 2 DM. However, future research with better quality still needs to be conducted to address the effects of Qigong on type 2 DM

    Reduced glutamine synthetase activity alters the fecundity of female Bactrocera dorsalis (Hendel)

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    Glutamine synthetase (GS) is a key enzyme in glutamine synthesis and is associated with multiple physiological processes in insects, such as embryonic development, heat shock response, and fecundity regulation. However, little is known about the influence of GS on female fecundity in the oriental fruit fly, Bactrocera dorsalis. Based on the cloning of BdGSs, mitochondrial BdGSm and cytoplasmic BdGSc, we determined their expressions in the tissues of adult B. dorsalis. BdGSm was highly expressed in the fat body, while BdGSc was highly expressed in the head and midgut. Gene silencing by RNA interference against two BdGSs isoforms suppressed target gene expression at the transcriptional level, leading to a reduced ovarian size and lower egg production. The specific inhibitor L-methionine S-sulfoximine suppressed enzyme activity, but only the gene expression of BdGSm was suppressed. A similar phenotype of delayed ovarian development occurred in the inhibitor bioassay. Significantly lower expression of vitellogenin and vitellogenin receptor was observed when GS enzyme activity was suppressed. These data illustrate the effects of two GS genes on adult fecundity by regulating vitellogenin synthesis in different ways
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