Fiscal Decentralization and Government Size: The Role of Democracy

This paper examines how the level of democracy in a country affects the relationship between fiscal decentralization and government size. We argue that political regimes, proxied by their democracy levels, are important for different decentralization theories to predict the impact of fiscal decentralization on government size. We test this argument using cross-country data from 76 developed and developing countries during 1972–2013. We find strong and robust evidence that fiscal decentralization is negatively associated with government size and that a higher level of democracy tends to mitigate the negative impact of fiscal decentralization. Therefore, our study contributes to the literature by offering a novel insight on mixed results regarding the relationship between fiscal decentralization and government size in the literature

Carbon Hybrids Electrocatalysts for Oxygen Reduction Reaction in Fuel Cells

PhDThe oxygen reduction reaction (ORR) is a key reaction in fuel cells and metal-air batteries. This process involves multi-electron transfer and is kinetically sluggish due to the high-energy barriers required to break the O-O bond. Current commercial Pt-C electrocalysts for the ORR suffer from high-cost and easy degradation; therefore, the development and rational design of alternative electrocatalysts for the ORR are important. Numerous efforts have been devoted to the development of environmentally benign electrocatalysts of high-performance and low cost. Among those, carbon-based materials have been considered promising alternatives for Pt-free ORR due to their distinct advantages such as high electrical conductivity, low cost, stable physical, and chemistry properties. This thesis includes the synthesis of hydrothermal carbon-graphene hybrid materials as electrocatalysts for ORR, and the engineering on the interface of carbon electrocatalysts at the triple point for enhanced ORR performance. The fundamental knowledge and the research background are introduced and summarized in Chapter 1 and Chapter 2, Chapter 3, respectively. The innovative research work is presented in the subsequent chapters: In Chapter 5, N-doped nanocarbon/graphene composites were carefully designed as electrocatalysts in ORR, in order to decouple the influence of active sites and electric conductivity, and investigate the underlying relationships between them. Results show that a low conductivity limits the exertion of active sites and results in a conductivity-dependent ORR activity. However, when the conductivity reaches critical value, the active sites can be fully utilized and contribute to a positively correlated ORR activity In Chapter 6, an effective strategy was proposed to enhance the oxygen reduction reaction (ORR) performance of MWCNTs in both acid and alkaline electrolytes by coating them with a layer of biomass derivative N-doped hydrothermal carbons. The N-doped amorphous carbon (NC) coating plays triple roles: it (i) promotes the assembly of MWCNTs into a 3D network therefore improving the mass transfer, thus increasing the catalytic activity; (ii) protects the surface present Fe-containing active sites on the MWCNTs from H2O2 poisoning; (iii) creates nitrogenated active sites and hence further enhances ORR activity and robustness. In Chapter 7, a novel and general concept was reported to improve the performance of Pt-free electrocatalysts in oxygen reduction reaction. This concept is based on the addition of oxygenophilic and hydrophobic ionic liquids (ILs) into Pt-free carbon catalyst to form a thin passivating layer at the triple point between the electrocatalyst-electrolyte-gas interface. The IL layer at the catalyst’s surface provides a water-equilibrated secondary medium with a higher O2 solubility, while its hydrophobic nature prevents water from building-up locally. It was also confirmed that the use of a protic ILs favours the ORR in both acid and alkaline media. This concept not only shows significant improvements in ORR in both alkaline and acid electrolyte, but also represents a promising method to be implemented in other renewable energy technologies (i.e. metal-air batteries, supercapacitors) where nanocarbons with improved surface properties are required.China Scholarship Council and Queen Mary University of London CSC-QMU

Active sites engineering leads to exceptional ORR and OER bifunctionality in P,N Co-doped graphene frameworks

Bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are highly desirable for rechargeable metal-air batteries and regenerative fuel cells. However, the commercial oxygen electrocatalysts (mainly noble metal based) can only exhibit either ORR or OER activity, and also suffer from inherent cost and stability issues. It remains challenging to achieve efficient ORR and OER bifunctionality on a single catalyst. Metal-free structures offer relatively large scope for such bifunctionality to be enginnered within one catalyst, together with improved cost-effectiveness and durablility. Herein, by closely coupled computational design and experimental development, highly effective bifunctionality is achieved in a phosphorus and nitrogen co-doped graphene framework (PNGF) - with both ORR and OER activities reaching the theoretical limits of metal-free catalysts, superior to the noble metal counterparts in both (bi)functionality and durability. In particular, with the identification of active P-N sites for OER and N-doped sites for ORR , we successfully intensified such sites by one-pot synthesis to tailor the PNGF. The resulting catalyst reaches an ORR potential of 0.845 V vs. RHE at 3 mA cm-2 and an OER potential of 1.55 V vs. RHE at 10 mA cm-2, respectively. Its combined ORR and OER overpotential of 705 mV is significantly lower than those reported previously for metal-free bifunctional catalysts

Progress in the diagnosis of lymph node metastasis in rectal cancer: a review

Historically, the chief focus of lymph node metastasis research has been molecular and clinical studies of a few essential pathways and genes. Recent years have seen a rapid accumulation of massive omics and imaging data catalyzed by the rapid development of advanced technologies. This rapid increase in data has driven improvements in the accuracy of diagnosis of lymph node metastasis, and its analysis further demands new methods and the opportunity to provide novel insights for basic research. In fact, the combination of omics data, imaging data, clinical medicine, and diagnostic methods has led to notable advances in our basic understanding and transformation of lymph node metastases in rectal cancer. Higher levels of integration will require a concerted effort among data scientists and clinicians. Herein, we review the current state and future challenges to advance the diagnosis of lymph node metastases in rectal cancer

New charmonium-like states

In recent years the B-factories and other machines have found evidence for a large number of new states with hidden charm: candidate h_c(1P), eta_c(2S), and chi_{c2}(2P) states; the well-established X(3872); enhancements called X(3940), Y(3940), and Y(4260); and a new structure at 4350 MeV. Various conventional-charmonium and more exotic interpretations of these data have been proposed. In this talk we review the current state of the experimental evidence and the prospects for clarifying the spectrum.Comment: 6 pages, 5 figures. To appear in the proceedings of Beauty 200

Geometric Nonlinear Meshless Analysis of Ribbed Rectangular Plates Based on the FSDT and the Moving Least-Squares Approximation

Based on the first-order shear deformation theory (FSDT) and the moving least-squares approximation, a new meshless model to study the geometric nonlinear problem of ribbed rectangular plates is presented. Considering the plate and the ribs separately, the displacement field, the stress, and strain of the plate and the ribs are obtained according to the moving least-squares approximation, the von Karman large deflection theory, and the FSDT. The ribs are attached to the plate by considering the displacement compatible condition along the connections between the ribs and the plate. The virtual strain energy formulation of the plate and the ribs is derived separately, and the nonlinear equilibrium equation of the entire ribbed plate is given by the virtual work principle. In the new meshless model for ribbed plates, there is no limitation to the rib position; for example, the ribs need not to be placed along the mesh lines of the plate as they need to be in FEM, and the change of rib positions will not lead to remeshing of the plate. The proposed model is compared with the FEM models from pieces of literature and ANSYS in several numerical examples, which proves the accuracy of the model

Erosion Wear Characteristics and Failure Mechanism of the Sulzer Oil Pump

In the routine maintenance of each main pump in the oil transmission station plant, abnormal erosion wear was found at the flushing port of the mechanical seal of Sulzer pump casing. For the sake of stable and safe unit operation, this study explored the mechanism and process of erosion formation in the pump casing at the microscopic level using SEM (scanning electron microscope) and EDS (energy dispersive spectrometer) techniques. And ANSYS Fluent was used to numerically simulate the unconventional turbulent flow in the special location of Sulzer pump to obtain its flow field characteristics. The trajectory tracking of solid phase particles based on Finnie erosion model was also carried out to obtain the influence law of different particle sizes on the wear degree of each area of the pump casing, and to point out the influence of the motion behavior of particles at the flushing port position on the erosion. The results show that there is unconventional turbulence in the flushing port of the Sulzer pump mechanical seal, and the solid particles are affected by turbulent diffusion and fluid adhesion, and some particles deviate from the velocity direction and continuously impact the surface of the pump casing, which is the direct cause of the erosion wear here. By optimizing the location of the flushing port, severe erosion wear at the flushing port can be avoided. This study can provide guidance and recommendations for the production, operational stability and wear protection of Sulzer pumps

The Y(4260) as an omega chi_{c1} molecular state

It is suggested that the newly observed Y(4260) by BARBAR collaboration is a molecular state composed of an omega and a chi_{c1}. Both the production and decay properties are discussed. A consequence for this molecular state, Y(4260), is that it decays into pi+pi-pi0 chi_{c1} with similar rate to pi+ pi- J/psi. It is also expected that Y(4260) -> pi0 pi0 J/psi is produced at half rate as Y(4260) ->pi+ pi- J/psi. These decay modes should be searched for in the B factories using initial state radiative return data and B decay data as well.Comment: 5 pages, 5 figure

Circular RNA Expression in the Brain of a Neonatal Rat Model of Periventricular White Matter Damage

Background/Aims: Periventricular white matter damage (PWMD) is the predominant neurologic lesion in preterm infants who survive brain injury. In this study, we assessed the global changes in and characteristics of the transcriptome of circular RNAs (circRNAs) in the brain tissues of rats with PWMD. Methods: We compared the expression profiles of circRNAs in brain samples from three rats with PWMD and three paired control tissues using deep RNA sequencing. Bioinformatics analysis was applied to investigate these differentially expressed circRNAs, and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis was performed to confirm the results. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to predict associated cell signaling pathways and functions. Network analysis was performed to predict circRNAs-microRNAs, and target genes related to PWMD. Results: A total of 2151 more reliable circRNAs were dysregulated in the brain tissues of rats with PWMD, indicating a potential role in the condition. Of the 98 circRNAs significantly differentially expressed in rat brains with PWMD (P< 0.05), 52 were significantly over-expressed and 46 were significantly under-expressed. The expression profiles of seven of 10 randomly selected circRNAs were confirmed by qRT-PCR analysis. The glutamatergic synapse pathway and the VEGF signaling pathway, both associated with hypoxia/ischemia induced brain damage, were inriched. Relationship between miRNA (rno-miR-433-3p and rno-miR-206-3p) and HIF-1α were evident and potential associations between chr6: 48820833|48857932 and their target genes (rno-miR-433-3p and rno-miR-206-3p) were identified. Conclusion: The distinct expression patterns of circRNAs in the brain tissues of rats with PWMD suggest that circRNAs actively respond to hypoxia-ischemia. These findings could assist the development of novel diagnostic and therapeutic targets for PWMD therapy