870 research outputs found

    The political economy of trade and growth: an analytical interpretation of sir James Steuart's inquiry

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    Sir James Steuart (1713-80) has been unduly neglected by the majority of historians of economic thought. This study aims at casting a new light upon his original thought to provide a basis for the revaluation of his contribution to the development of economic discipline. The present interpretation of his Inquiry (1767) reveals that his political economy contains not only fresh new ideas and path-breaking thinking for his time but also most major ingredients of modem economics. Firmly based on the recognition of the interdependence of economic sectors and social classes, he clearly grasped the circular system of production, distribution and consumption in the exchange economy. He discerned between the 'profit upon alienation' and the 'real value' of commodities in their current price' determined in the markets. He emphasized the 'balance of work and demand', secured by the 'double competition' among the sellers and buyers of commodities, for the efficient allocation of economic resources. On these foundations, Steuart established his theory of output, employment and population in terms of the notion of 'effectual demand'. His economic analysis culminates in his discussions of economic growth and foreign trade. He linked the limitations of the former to the benefits of the latter. Meanwhile, refuting his predecessors' quantity theory, Steuart presented what might be called the production-consumption theory of money, according to which money is not neutral to the determination of the level of output in an exchange economy. His theory of international money also takes on modernity, as it adopts an absorption approach to the balance of payments. Steuart's monetary analysis comes complete with his argument for government's active finance. The state interventionism underlying the whole of Steuart's political economy is seen as its logical conclusion, rather than a mere assumption. Thus, it is suggested that the ultimate message of his Inquiry is neither laissez faire nor centa-al planning

    Separable PINN: Mitigating the Curse of Dimensionality in Physics-Informed Neural Networks

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    Physics-informed neural networks (PINNs) have emerged as new data-driven PDE solvers for both forward and inverse problems. While promising, the expensive computational costs to obtain solutions often restrict their broader applicability. We demonstrate that the computations in automatic differentiation (AD) can be significantly reduced by leveraging forward-mode AD when training PINN. However, a naive application of forward-mode AD to conventional PINNs results in higher computation, losing its practical benefit. Therefore, we propose a network architecture, called separable PINN (SPINN), which can facilitate forward-mode AD for more efficient computation. SPINN operates on a per-axis basis instead of point-wise processing in conventional PINNs, decreasing the number of network forward passes. Besides, while the computation and memory costs of standard PINNs grow exponentially along with the grid resolution, that of our model is remarkably less susceptible, mitigating the curse of dimensionality. We demonstrate the effectiveness of our model in various PDE systems by significantly reducing the training run-time while achieving comparable accuracy. Project page: https://jwcho5576.github.io/spinn/Comment: To appear in NeurIPS 2022 Workshop on The Symbiosis of Deep Learning and Differential Equations (DLDE) - II, 12 pages, 5 figures, full paper: arXiv:2306.1596

    Separable Physics-Informed Neural Networks

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    Physics-informed neural networks (PINNs) have recently emerged as promising data-driven PDE solvers showing encouraging results on various PDEs. However, there is a fundamental limitation of training PINNs to solve multi-dimensional PDEs and approximate highly complex solution functions. The number of training points (collocation points) required on these challenging PDEs grows substantially, but it is severely limited due to the expensive computational costs and heavy memory overhead. To overcome this issue, we propose a network architecture and training algorithm for PINNs. The proposed method, separable PINN (SPINN), operates on a per-axis basis to significantly reduce the number of network propagations in multi-dimensional PDEs unlike point-wise processing in conventional PINNs. We also propose using forward-mode automatic differentiation to reduce the computational cost of computing PDE residuals, enabling a large number of collocation points (>10^7) on a single commodity GPU. The experimental results show drastically reduced computational costs (62x in wall-clock time, 1,394x in FLOPs given the same number of collocation points) in multi-dimensional PDEs while achieving better accuracy. Furthermore, we present that SPINN can solve a chaotic (2+1)-d Navier-Stokes equation significantly faster than the best-performing prior method (9 minutes vs 10 hours in a single GPU), maintaining accuracy. Finally, we showcase that SPINN can accurately obtain the solution of a highly nonlinear and multi-dimensional PDE, a (3+1)-d Navier-Stokes equation.Comment: arXiv admin note: text overlap with arXiv:2211.0876

    Changes in Oral Vowel Sounds and Hyoid Bone Movement After Thyroidectomy

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    Objectives Voice and speech alterations after total thyroidectomy may be associated with other extralaryngeal factors, such as neck muscle dysfunction and neck scar contracture. We evaluated the acoustic characteristics of oral vowel sounds and changes in hyoid bone movement before and after thyroidectomy. Methods Twenty-nine female patients undergoing total thyroidectomy were included. Fundamental frequencies (Fo), formants and vowel space areas were evaluated before surgery and 7 days and 3 months after surgery to acoustically analyze the oral vowel sounds. Videofluoroscopic images were taken at the same times to evaluate hyoid bone movement. Results The Fo levels of seven vowels decreased significantly after surgery. The vowel formant changes the F1 of vowel /[e]/ decreased significantly from baseline at 3 months postoperatively, and the F3 of vowel /[i]/ decreased significantly from baseline 7 days postoperatively. The change in the vowel space area was not observed. The Y coordinate of the vowels /[i]/ and /[e]/ decreased significantly from baseline 7 days postoperatively due to changes in hyoid movement. Conclusion The damage to the neck muscles after thyroidectomy changes in Fo, formant and hyoid bone position. These quantitative results could be used as basic data for voice management in patients who undergo thyroidectomy

    Anti-inflammatory activity of cinnamon water extract in vivo and in vitro LPS-induced models

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    BACKGROUND: Cinnamon bark is one of the most popular herbal ingredients in traditional oriental medicine and possesses diverse pharmacological activities including anti-bacterial, anti-viral, and anti-cancer properties. The goal of this study is to investigate the in vivo and in vitro inhibitory effect of cinnamon water extract (CWE) on lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α and its underlying intracellular mechanisms. METHODS: CWE was orally administrated to mice for 6 days prior to intraperitoneal injection of LPS. Serum levels of TNF-α and interleukin (IL)-6 were determined 1 hour after LPS stimulation. Peritoneal macrophages from thioglycollate-injected mice were isolated and assayed for viability, cytokine expression and signaling molecules upon LPS stimulation. CWE was further fractioned according to molecular size, and the levels of total polyphenols and biological activities of each fraction were measured. RESULTS: The oral administration of CWE to mice significantly decreased the serum levels of TNF-α and IL-6. CWE treatment in vitro decreased the mRNA expression of TNF-α. CWE blocked the LPS-induced degradation of IκBα as well as the activation of JNK, p38 and ERK1/2. Furthermore, size-based fractionation of CWE showed that the observed inhibitory effect of CWE in vitro occurred in the fraction containing the highest level of total polyphenols. CONCLUSIONS: Treatment with CWE decreased LPS-induced TNF-α in serum. In vitro inhibition of TNF-α gene by CWE may occur via the modulation of IκBα degradation and JNK, p38, and ERK1/2 activation. Our results also indicate that the observed anti-inflammatory action of CWE may originate from the presence of polyphenols

    Reinterpretation of anthocyanins biosynthesis in developing black rice seeds through gene expression analysis

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    The biosynthesis of anthocyanins is still questionable in regulating the quantities of anthocyanins biosynthesized in rice seeds and the expression levels of transcription factors and the structural genes involved in the biosynthetic pathway of anthocyanins. We herein investigated the relationship between the accumulated anthocyanin contents and the expression levels of genes related to the biosynthesis of anthocyanins in rice seeds. Liquid chromatography/mass spectrometry-mass spectrometry analysis of cyanidin 3-glucoside (C3G) in rice seeds showed no accumulation of C3G in white and red rice cultivars, and the differential accumulation of C3G among black rice cultivars. RNA-seq analysis in rice seeds, including white, red, and black rice cultivars, at twenty days after heading (DAH) further exhibited that the genes involved in the biosynthesis of anthocyanins were differentially upregulated in developing seeds of black rice. We further verified these RNA-seq results through gene expression analysis by a quantitative real-time polymerase chain reaction in developing seeds of white, red, and black rice cultivars at 20 DAH. Of these genes related to the biosynthesis of anthocyanins, bHLHs, MYBs, and WD40, which are regulators, and the structural genes, including chalcone synthase (CHS), flavanone 3-hydroxylase (F3H), flavonoid 3´-hydroxylase (F3´H), dihydroflavonol 4-reductase (DFR), and anthocyanidin synthase (ANS), were differentially upregulated in black rice seeds. The correlation analysis revealed that the quantities of C3G biosynthesized in black rice seeds were positively correlated to the expression levels of bHLHs, MYBs and WD40, CHS, F3H, F3´H, DFR, and ANS. In addition, we present bHLH2 (LOC_Os04g47040) and MYBs (LOC_Os01g49160, LOC_Os01g74410, and LOC_Os03g29614) as new putative transcription factor genes for the biosynthesis of anthocyanins in black rice seeds. It is expected that this study will help to improve the understanding of the molecular levels involved in the biosynthesis of anthocyanins in black rice seeds
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