209 research outputs found

    Components of AR-quivers for string algebras of type C˜ and a conjecture by Geiss-Leclerc-Schröer

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    We study modules of certain string algebras, which are referred to as of affine type C˜. We introduce minimal string modules and apply them to explicitly describe components of the Auslander-Reiten quivers of the string algebras and τ-locally free modules defined by Geiss-Lerclerc-Schröer. In particular, we show that an indecomposable module is τ-locally free if and only if it is preprojective, or preinjective or regular in a tube. As an application, we prove Geiss-Leclerc-Schröer's conjecture on the correspondence between positive roots of type C˜ and τ-locally free modules of the corresponding string algebras. Furthermore, given a positive root α, we show that if α is real, then there is a unique τ-locally free module M (up to isomorphism) with rank_M=α; otherwise there are families of τ-locally free modules with rank_M=α.</p

    Components of AR-quivers for string algebras of type C˜ and a conjecture by Geiss-Leclerc-Schröer

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    We study modules of certain string algebras, which are referred to as of affine type C˜. We introduce minimal string modules and apply them to explicitly describe components of the Auslander-Reiten quivers of the string algebras and τ-locally free modules defined by Geiss-Lerclerc-Schröer. In particular, we show that an indecomposable module is τ-locally free if and only if it is preprojective, or preinjective or regular in a tube. As an application, we prove Geiss-Leclerc-Schröer's conjecture on the correspondence between positive roots of type C˜ and τ-locally free modules of the corresponding string algebras. Furthermore, given a positive root α, we show that if α is real, then there is a unique τ-locally free module M (up to isomorphism) with rank_M=α; otherwise there are families of τ-locally free modules with rank_M=α.</p

    What Determine China’s Inflation?

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    We examine determinants of inflation in China. Analyses of both yearonyear and monthonmonth growth data confirm excess liquidity, output gap, housing prices and stock prices positively affecting inflation. Impulse response analyses indicate that most effects occur during the initial five months and disappear after 10 months. Effects of real interest rates and exchange rates on inflation are relatively weak. Our results suggest that output gap is as important as excess liquidity in explaining inflation trajectory. The central bank should closely monitor asset prices given their spillovers to inflation. Currently liquidity measures are still central for controlling inflation, but further liberalization of interest rates and exchange rates are critical.China, inflation, excess liquidity

    Understanding China’s fintech sector: development, impacts and risks

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    Financial technology (fintech) is rapidly transforming the economy as well as the financial landscape in China. This paper attempts to shed light on its contributing factors, current state, economic impacts and potential risks. We identify three key drivers for China’s fintech development, namely shortage of supply in formal financial market, strong government support for promoting financial inclusion through digital technology, and more ‘tolerant’ regulatory environment. The greatest value of the Chinese fintech sector is promotion of financial inclusion, enabling a vast number of small- and medium-sized enterprises (SMEs) and low-income households to access to financial services. Existing studies unveil some strong evidences of fintech development improving efficiency, increasing employment and supporting entrepreneurship. In the meantime, there are also serious challenges facing this sector, such as regulatory uncertainties, illegal transactions, data abuse, etc. We conclude the paper by presenting some key takeaways, including several lessons for financial regulation

    Tadalafil-loaded PLGA microspheres for pulmonary administration: preparation and evaluation

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    Tadalafil, a long-acting PED-5 inhibitor, is commonly used for the treatment of pulmonary arterial hypertension (PAH). However, its efficacy and clinical application are severely limited by the poor water solubility, low bioavailability and a series adverse effects (e.g. headaches, indigestion). In this study, tadalafil was prepared and loaded into biodegradable PLGA (poly(lactic-co-glycolic acid)) microspheres (TDF-PLGA-MS) via emulsification-solvent evaporation. The resulting microspheres were processed into pulmonary inhalant by freeze drying. The TDF-PLGA-MS was spherical and uniform, with an average particle diameter ~10.29 μm. The encapsulation efficiency and drug loading yield of TDF‑PLGA‑MS were 81.68% and 8.52%, respectively. The investigation of micromeritics showed that the TDF‑PLGA‑MS had low moisture content. The fluidity of powders was relatively good. The aerodynamic diameter and emptying rate of microspheres powders were 3.92 μm and 95.41%, respectively. Therefore, the microspheres powders were easy to be atomized, and can meet the requirements of pulmonary administration. In vitro release results showed that the microspheres group released slowly. The cumulative release in 24 h and 10 d was 46.87% and 84.06%, respectively. The in vitro release profile of TDF‑PLGA‑MS was in accordance with the Weibull model. The results of Pharmacokinetics showed that tadalafil from microspheres slowly released into the blood after intratracheal instillation. The pulmonary drug residue in 0.5 h was 3.5 times compared with solution group. The residual concentration in lung after 10d was still higher than that of solution group in 48 h. The t1/2β and MRT0-∞ were 3.10 times and 3.96 times that of solution group, respectively. Moreover, the Cmax and AUC of drug residues in lung were 3.48 times and 16.36 times that of solution group, respectively. The results of tissue distribution showed that the Re in lung was 16.358, which indicated the lung targeting. In conclusion, the TDF-PLGA-MS for pulmonary administration in this study can significantly improve the pulmonary targeting, increase efficacy of tadalafil and reduce other non-target organs toxicity. This study will have an important clinical significance for PAH patients who need long-term drug therapy

    The Influence of Carrier's Attitude and the Position Reduction in Multibeam Echosounding and Airborne Laser Depth Sounding

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    Having finished the development of the multibeam echosounding system, China is making a great effort to develop an airborne laser depth sounding system. According to the principle of the two kinds of sounding system mentioned above, a series of position reduction formulas and their error equations are developed in this paper. The dynamic effect of marine sounding, i.e., the influence of carrier's attitude, is taken into full account in developing the equations. Finally, the real parameters of the two sounding systems developed by China are used to calculate the position reductions and their accuracies at different heading angles. The results show that the accuracies of depths and positions in multibeam echosounding and airborne laser depth sounding are dependent not only on their own sensors but also on the additional sensors

    Coastal wetland mapping with sentinel-2 MSI imagery based on gravitational optimized multilayer perceptron and morphological attribute profiles.

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    Coastal wetland mapping plays an essential role in monitoring climate change, the hydrological cycle, and water resources. In this study, a novel classification framework based on the gravitational optimized multilayer perceptron classifier and extended multi-attribute profiles (EMAPs) is presented for coastal wetland mapping using Sentinel-2 multispectral instrument (MSI) imagery. In the proposed method, the morphological attribute profiles (APs) are firstly extracted using four attribute filters based on the characteristics of wetlands in each band from Sentinel-2 imagery. These APs form a set of EMAPs which comprehensively represent the irregular wetland objects in multiscale and multilevel. The EMAPs and original spectral features are then classified with a new multilayer perceptron (MLP) classifier whose parameters are optimized by a stability-constrained adaptive alpha for a gravitational search algorithm. The performance of the proposed method was investigated using Sentinel-2 MSI images of two coastal wetlands, i.e., the Jiaozhou Bay and the Yellow River Delta in Shandong province of eastern China. Comparisons with four other classifiers through visual inspection and quantitative evaluation verified the superiority of the proposed method. Furthermore, the effectiveness of different APs in EMAPs were also validated. By combining the developed EMAPs features and novel MLP classifier, complicated wetland types with high within-class variability and low between-class disparity were effectively discriminated. The superior performance of the proposed framework makes it available and preferable for the mapping of complicated coastal wetlands using Sentinel-2 data and other similar optical imagery
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