150 research outputs found
Essays on Federalism and Local Finance in China
This dissertation consists of three chapters that cover topics on federalism and local finance in China.
Chapter 1 - Economic Growth, Fiscal Inequality and Fiscal Decentralization: Evidence from China.
This paper investigates the impact of inequality in the geographic distribution of fiscal resources on regional economic growth under fiscal decentralization policy in the context of China\u27s experience, using panel data for 28 provinces over the period 1987–2010. In the recent past, the structure of decentralized government in China has undergone two significant fiscal reforms: the ``Fiscal Responsibility System (FRS) in 1987-1993, and the ``Tax Sharing System (TSS) in 1994. I find that there are different impacts of overall fiscal inequality on economic growth pre-and post-1994. Second, I show that fiscal decentralization could improve regional growth in China. Finally, this paper finds that the use of extra-budgetary funds could reduce the economic growth gap between rich and poor provinces.
Chapter 2 - Fiscal Decentralization and Local Economic Growth.
This paper develops an endogenous growth model with spillovers of public goods and mobile capital to examine economic growth and social welfare under decentralized and centralized systems. I first consider a setting with an exogenous ratio of productive government expenditure to the total expenditure and then a model with the endogenous ratio. In both cases, growth rates are lower and social welfare is higher for both the developed and the less-developed regions in the centralized system than in decentralized systems. Finally, I also use a fiscal decentralization reform in China – namely, the province-managing-county (PMC) reform – to examine the effects of fiscal decentralization on local economic growth. The PMC reform abolished the subordinate fiscal relationship between prefectures and counties and transferred much of the tax and spending authority from the prefecture to the county level.
Chapter 3 - Local Fiscal Competition and Deficits in China (with Timothy J. Goodspeed).
This paper adds to the literature by examining fiscal competition and deficit financing by local governments in a developing country, China. We examine a unique revenue source in China, land-use premiums (a type of property tax), in a panel dataset consolidated at the prefectural level from 2006 to 2016. Our results indicate that fiscal competition in land-use premiums exists and is stronger among wealthier than poorer local governments, a result that supports the view of \cite{cai2005does} that competition among asymmetrically endowed regions can lead to less discipline. Moreover, we find higher local deficits are associated with lower land-use premiums, a result that suggests that the local government does not fill any fiscal gap with own revenues
Recent Advances of ZnO-Based Perovskite Solar Cell
Perovskite solar cells (PSCs) have developed rapidly over the past few years, and the power conversion efficiency (PCE) of PSCs has exceeded 25%. It has the characteristics of low cost, high efficiency, simple process and so on, and hence has a good development prospect. Due to the difference in electrons and holes diffusion lengths, electron transporting materials (ETMs) play a crucial role in the performance of PSCs. ZnO electron transport layer (ETL) has the advantages of high electron mobility, high transmittance, suitable energy level matching with neighbor layer in PSCs, low temperature preparation and environmental friendliness, so it has become the main application material of electron transport layer in perovskite solar cells. In this review, the application of ZnO-ETMs in PSCs in recent years is reviewed, and the effect of ZnO-ETMs on the performance of PSCs is also introduced. Finally, the limitations of ZnO-ETMs based PSCs and the methods to solve these problems are discussed, and the development prospect of PSCs is prospected
Surfactant spreading on liquid films in the Stokes regime
Characterizing the spreading of surfactants on the surface of a liquid film is central to our understanding of natural and technological processes ranging from cell propulsion and drug delivery in pulmonary airways to cleaning food processing surfaces. In this work, we analyze the spreading dynamics of a drop of insoluble surfactants in a perfectly viscous (i.e., Stokes) regime. Using simple scaling arguments, we estimate that the size of a small surfactant drop grows as a power-law with time with an exponent of 1/3. The estimated scaling is then corroborated and better characterized using direct numerical simulations. Furthermore, the simulation results help establish the transition from the initial 1/3 scaling with time to the later 1/4 scaling that is expected when the spreading drop grows larger than the film thickness.Fil: Lu, Jiakai. Massachusetts Institute of Technology; Estados UnidosFil: Zhang, Qian. Purdue University; Estados UnidosFil: Ubal, Sebastian. Universidad Nacional de Entre Ríos. Instituto de Investigación y Desarrollo en Bioingeniería y Bioinformática - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación y Desarrollo en Bioingeniería y Bioinformática; ArgentinaFil: Corvalan, Carlos M.. Purdue University; Estados Unido
Spatiotemporal Characteristics of Particulate Matter and Dry Deposition Flux in the Cuihu Wetland of Beijing
In recent years, the rapid development of industrialization and urbanization has caused serious environmental pollution, especially particulate pollution. As the “Earth’s kidneys,” wetland plays a significant role in improving the environmental quality and adjusting the climate. To study how wetlands work in this aspect, from the early autumn of 2014 to 2015, we implemented a study to measure the PM concentration and chemical composition at three heights (1.5, 6, and 10 m) during different periods (dry, normal water, and wet periods) in the Cuihu wetland park in Beijing for analyzing the dry deposition flux and the effect of meteorological factors on the concentration. Results indicated that (1) the diurnal variations of the PM2.5 and PM10 concentrations at the three heights were similar in that the highest concentration occurred at night and the lowest occurred at noon, and the daytime concentration was lower than that at night; (2) the PM2.5 and PM10 concentrations also varied between different periods that wet period \u3e normal water period \u3e wet period, and the concentration at different heights during different periods varied. In general, the lowest concentration occurred at 10 m during the dry and normal water periods, and the highest concentration occurred at 1.5 m during the wet period. (3) SO4 2− , NO3 − , and Cl− are the dominant constituents of PM2.5, accounting for 42.22, 12.6, and 21.56%, respectively; (4) the dry depositions of PM2.5 and PM10 at 10 m were higher than those at 6 m, and the deposition during the dry period was higher than those during the wet and normal water periods. In addition, the deposition during the night-time was higher than that during the daytime. Moreover, meteorological factors affected the deposition, the temperature and wind speed being negatively correlated with the deposition flux and the humidity being positively correlated. (5) The PM10 and PM2.5 concentrations were influenced by meteorological factors. The PM2.5 and PM10 concentrations were negatively correlated with temperature and wind speed but positively correlated with relative humidity
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An In Vitro Comparison of the Digestibility and Gastrointestinal Fate of Scallops and Plant-Based Scallop Analogs
Concerns exist regarding the negative environmental impact and health risks associated with ocean fishing and aquaculture, such as stock depletion, pollution, biodiversity loss, and toxin presence. To address these concerns, plant-based seafood analogs are being developed. Our previous study successfully created plant-based scallop analogs using pea proteins and citrus pectin, resembling real scallops in appearance and texture. This study focuses on comparing the digestive fate of these analogs to real scallops, as it can impact their nutritional properties. Using an in vitro digestion model (INFOGEST), we simulated oral, gastric, and small intestinal conditions. The analysis revealed differences in the microstructure, physicochemical properties, and protein digestibility between the plant-based scallops and real scallops. The particle size and charge followed the following similar trends for both types of scallops: the particle size decreased from the mouth to the stomach to the small intestine; the particles were negative in the mouth, positive in the stomach, and negative in the small intestine. The protein digestibility of the plant-based scallops was considerably lower than that of real scallops. For instance, around 18.8% and 61.4% of protein was digested in the stomach and small intestine phases for the real scallop (80.2% total digestion), whereas around 8.7% and 47.7% of the protein was digested for the plant-based scallop (56.4% total digestion). The lower digestibility of the plant-based scallops may have been due to differences in the protein structure, the presence of dietary fibers (pectin), or antinutritional factors in the plant proteins. These findings are crucial for developing more sustainable next-generation plant-based seafood analogs
CryoFormer: Continuous Reconstruction of 3D Structures from Cryo-EM Data using Transformer-based Neural Representations
High-resolution heterogeneous reconstruction of 3D structures of proteins and
other biomolecules using cryo-electron microscopy (cryo-EM) is essential for
understanding fundamental processes of life. However, it is still challenging
to reconstruct the continuous motions of 3D structures from hundreds of
thousands of noisy and randomly oriented 2D cryo-EM images. Existing methods
based on coordinate-based neural networks show compelling results to model
continuous conformations of 3D structures in the Fourier domain, but they
suffer from a limited ability to model local flexible regions and lack
interpretability. We propose a novel approach, cryoFormer, that utilizes a
transformer-based network architecture for continuous heterogeneous cryo-EM
reconstruction. We for the first time directly reconstruct continuous
conformations of 3D structures using an implicit feature volume in the 3D
spatial domain. A novel deformation transformer decoder further improves
reconstruction quality and, more importantly, locates and robustly tackles
flexible 3D regions caused by conformations. In experiments, our method
outperforms current approaches on three public datasets (1 synthetic and 2
experimental) and a new synthetic dataset of PEDV spike protein. The code and
new synthetic dataset will be released for better reproducibility of our
results. Project page: https://cryoformer.github.io
VGOS: Voxel Grid Optimization for View Synthesis from Sparse Inputs
Neural Radiance Fields (NeRF) has shown great success in novel view synthesis
due to its state-of-the-art quality and flexibility. However, NeRF requires
dense input views (tens to hundreds) and a long training time (hours to days)
for a single scene to generate high-fidelity images. Although using the voxel
grids to represent the radiance field can significantly accelerate the
optimization process, we observe that for sparse inputs, the voxel grids are
more prone to overfitting to the training views and will have holes and
floaters, which leads to artifacts. In this paper, we propose VGOS, an approach
for fast (3-5 minutes) radiance field reconstruction from sparse inputs (3-10
views) to address these issues. To improve the performance of voxel-based
radiance field in sparse input scenarios, we propose two methods: (a) We
introduce an incremental voxel training strategy, which prevents overfitting by
suppressing the optimization of peripheral voxels in the early stage of
reconstruction. (b) We use several regularization techniques to smooth the
voxels, which avoids degenerate solutions. Experiments demonstrate that VGOS
achieves state-of-the-art performance for sparse inputs with super-fast
convergence. Code will be available at https://github.com/SJoJoK/VGOS.Comment: IJCAI 2023 Accepted (Main Track
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