552 research outputs found

    Social Capital, Endogenous Labor Supply, and Economic Development

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    Social capital has been increasingly recognized as an important determinant of economic growth in the literature of economic growth. Nevertheless, there are only a few rigorous dynamic growth models which explicitly deal with dynamic interdependence between social capital, physical capital, and economic structure. The purpose of this study is to incorporate social capital in a neoclassical economic growth theory. We propose a dynamic model with interdependence between economic structural change, wealth accumulation, and social capital accumulation. Social capital positively affects total factor productivities and is accumulated through investment, leisure activities, and production. We simulate the model. The study focuses on effects of changes in some parameters on the equilibrium and transitional processes of the economic dynamics. We get some insights through including social capital in economic growth modelling. For instance, if society has lower trust (possibly if we interpret social capital as guanxi in Chinese societies) which results in a rise in depreciation rate of social capital, the economy suffers from falling social capital, productivities, national capital, and national output; consumers have lower income, wealth, and consumption; they also have to spend more time on investing in social capital

    Economic Growth with Tourism and Environmental Change

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    The main purpose of this study is to examine dynamic interactions between economic growth, environmental change, and tourism. Although tourism is playing an increasingly important role in different economies, there are only a few theoretical models to dynamic economic and environmental issues with endogenous tourism. On the basis of the Solow-Uzawa growth model, the neoclassical growth model with environmental change, and ideas from tourism economics, we develop a three-sector growth model. The industrial and service sectors are perfectly competitive. The environment sector is financially supported by the government. We introduce taxes not only on producers, but also on consumers’ incomes from wage, land, and interest of wealth, consumption of goods and services, and housing. We simulate the motion of the national economy and examine effects of changes in some parameters. The comparative dynamic analysis with regard to the rate of interest, the price elasticity of tourism, the global economic condition, the total productivity of the service sectors, and the propensity to save provides some important insights into the complexity of open economies with endogenous wealth and environment

    Exact results for the extreme Thouless effect in a model of network dynamics

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    If a system undergoing phase transitions exhibits some characteristics of both first and second order, it is said to be of 'mixed order' or to display the Thouless effect. Such a transition is present in a simple model of a dynamic social network, in which NI/EN_{I/E} extreme introverts/extroverts always cut/add random links. In particular, simulations showed that f\left\langle f\right\rangle , the average fraction of cross-links between the two groups (which serves as an 'order parameter' here), jumps dramatically when ΔNINE\Delta \equiv N_{I}-N_{E} crosses the 'critical point' Δc=0\Delta _{c}=0, as in typical first order transitions. Yet, at criticality, there is no phase co-existence, but the fluctuations of ff are much larger than in typical second order transitions. Indeed, it was conjectured that, in the thermodynamic limit, both the jump and the fluctuations become maximal, so that the system is said to display an 'extreme Thouless effect.' While earlier theories are partially successful, we provide a mean-field like approach that accounts for all known simulation data and validates the conjecture. Moreover, for the critical system NI=NE=LN_{I}=N_{E}=L, an analytic expression for the mesa-like stationary distribution, P(f)P\left( f\right) , shows that it is essentially flat in a range [f0,1f0]\left[ f_{0},1-f_{0}\right] , with f01f_0 \ll 1. Numerical evaluations of f0f_{0} provides excellent agreement with simulation data for L2000L\lesssim 2000. For large LL, we find f0(lnL2)/Lf_{0}\rightarrow \sqrt{\left( \ln L^2 \right) /L} , though this behavior begins to set in only for L>10100L>10^{100}. For accessible values of LL, we provide a transcendental equation for an approximate f0f_{0} which is better than \sim1% down to L=100L=100. We conjecture how this approach might be used to attack other systems displaying an extreme Thouless effect.Comment: 6 pages, 4 figure

    An inspection technology of inner surface of the fine hole based on machine vision

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    Fine holes are an important structural component of industrial components, and their inner surface quality is closely related to their function.In order to detect the quality of the inner surface of the fine hole,a special optical measurement system was investigated in this paper. A sight pipe is employed to guide the external illumination light into the fine hole and output the relevant images simultaneously. A flexible light array is introduced to suit the narrow space, and the effective field of view is analyzed. Besides, the arc surface projection error and manufacturing assembly error of the device are analyzed, then compensated or ignored if small enough. In the test of prefabricated circular defects with the diameter {\phi}0.1mm, {\phi}0.2mm, 0.4mm distance distribution and the fissure defects with the width 0.3mm, the maximum measurement error standard deviation are all about 10{\mu}m. The minimum diameter of the measured fine hole is 4mm and the depth can reach 47mm

    Transferable Adversarial Attacks on Vision Transformers with Token Gradient Regularization

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    Vision transformers (ViTs) have been successfully deployed in a variety of computer vision tasks, but they are still vulnerable to adversarial samples. Transfer-based attacks use a local model to generate adversarial samples and directly transfer them to attack a target black-box model. The high efficiency of transfer-based attacks makes it a severe security threat to ViT-based applications. Therefore, it is vital to design effective transfer-based attacks to identify the deficiencies of ViTs beforehand in security-sensitive scenarios. Existing efforts generally focus on regularizing the input gradients to stabilize the updated direction of adversarial samples. However, the variance of the back-propagated gradients in intermediate blocks of ViTs may still be large, which may make the generated adversarial samples focus on some model-specific features and get stuck in poor local optima. To overcome the shortcomings of existing approaches, we propose the Token Gradient Regularization (TGR) method. According to the structural characteristics of ViTs, TGR reduces the variance of the back-propagated gradient in each internal block of ViTs in a token-wise manner and utilizes the regularized gradient to generate adversarial samples. Extensive experiments on attacking both ViTs and CNNs confirm the superiority of our approach. Notably, compared to the state-of-the-art transfer-based attacks, our TGR offers a performance improvement of 8.8% on average.Comment: CVPR 202

    Genetic variation in eight Chinese cattle breeds based on the analysis of microsatellite markers

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    Genetic variability and genetic relationships were investigated among eight Chinese cattle breeds using 12 microsatellite markers. Three hundred and fifty-two alleles were detected and the average number of alleles per locus ranged from 8.33 ± 1.67 in the Jiaxian breed to 21.33 ± 5.60 in the Qinchuan breed with a mean value of 13.91. The total number of alleles per microsatellite ranged from 21 (INRA005, HEL1) to 40 (HEL13), with a mean of 29.33 per locus. The fixation indices at the 12 loci in the eight breeds were very low with a mean of 0.006. A principal components analysis and the construction of a neighborjoining tree showed that these eight Chinese cattle breeds cluster into three groups i.e. the Yanbian andChineseHolstein, theNanyang and Jiaxian, and the four remaining breeds.This clustering agrees with the origin and geographical distributions of these Chinese breeds

    Identification of novel maize miRNAs by measuring the precision of precursor processing

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    <p>Abstract</p> <p>Background</p> <p>miRNAs are known to play important regulatory roles throughout plant development. Until recently, nearly all the miRNAs in maize were identified by comparative analysis to miRNAs sequences of other plant species, such as rice and <it>Arabidopsis</it>.</p> <p>Results</p> <p>To find new miRNA in this important crop, small RNAs from mixed tissues were sequenced, resulting in over 15 million unique sequences. Our sequencing effort validated 23 of the 28 known maize miRNA families, including 49 unique miRNAs. Using a newly established criterion, based on the precision of miRNA processing from precursors, we identified 66 novel miRNAs in maize. These miRNAs can be grouped into 58 families, 54 of which have not been identified in any other species. Five new miRNAs were validated by northern blot. Moreover, we found targets for 23 of the 66 new miRNAs. The targets of two of these newly identified miRNAs were confirmed by 5'RACE.</p> <p>Conclusion</p> <p>We have implemented a novel method of identifying miRNA by measuring the precision of miRNA processing from precursors. Using this method, 66 novel miRNAs and 50 potential miRNAs have been identified in maize.</p

    Analysis of molecular mechanisms of drug resistance of Mycobacterium tuberculosis in patients with pulmonary tuberculosis and its pharmacoeconomics

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    Purpose: To investigate the molecular mechanisms of drug resistance of Mycobacterium tuberculosis in patients with pulmonary tuberculosis and its pharmacoeconomics. Methods: Data pertaining to patients with primary tuberculosis treated in the First Affiliated Hospital of Zhaoqing Medical College, Zhaoqing, China from January 2020 to June 2021 were retrospectively analyzed. Sputum specimens were collected from all eligible patients, and 151 uncontaminated specimens with good bacteriophage activity were screened. Results: A total of 107 Mycobacterium tuberculosis strains were isolated from the 151 specimens, 31 of which strains were resistant to varying degrees to rifampicin, isoniazid, streptomycin, and ethambutol with an overall resistance of 28.97 %. There were 16 strains with rpoB mutation, 22 strains with katG mutation, and 8 strains with inhA mutation. The difference in the sputum negative rate, lesion absorption rate, and tuberculosis cavity closure rate, and total medical cost between the two group were not statistically significant (p &gt; 0.05). The incidence of adverse reactions in the FDC group was significantly lower than that in the blister pack group (p &lt; 0.05). Conclusion: The total resistance of Mycobacterium tuberculosis in primary tuberculosis patients remains at a high level, and the development of resistance is associated with mutations in rpoB, katG, and inhA genes. FDC regimen provides more pharmacoeconomic and therapeutic benefits than blister pack regimen
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