Anti-resonance, inhibited coupling and mode transition in depressed core fibers

The depressed core fiber (DCF), consisting of a low-index solid core, a high-index cladding and air surrounding, is in effect a bridge between the conventional step-index fiber and the tube-type hollow-core fiber from the point of view of the index profile. In this paper the dispersion diagram of a DCF is obtained by solving the full-vector eigenvalue equations and analyzed using the theory of anti-resonant and the inhibited coupling mechanisms. While light propagation in tube-type hollow-core fibers is commonly described by the symmetric planar waveguide model, here we propose an asymmetric planar waveguide for the DCFs in an anti-resonant reflecting optical waveguide (ARROW) model. It is found that the anti-resonant core modes in the DCFs have real effective indices, compared to the anti-resonant core modes with complex effective indices in the tube-type hollow-core fibers. The anti-resonant core modes in the DCFs exhibit similar qualitative and quantitative behavior as the core modes in the conventional step-index fibers. The full-vector analytical results for the simple-structure DCFs can contribute to a better understanding of the anti-resonant and inhibited coupling guidance mechanisms in other complex inversed index fibers

Cryo-EM structure of the mature dengue virus at 3.5-Å resolution.

Regulated by pH, membrane-anchored proteins E and M function during dengue virus maturation and membrane fusion. Our atomic model of the whole virion from cryo-electron microscopy at 3.5-Å resolution reveals that in the mature virus at neutral extracellular pH, the N-terminal 20-amino-acid segment of M (involving three pH-sensing histidines) latches and thereby prevents spring-loaded E fusion protein from prematurely exposing its fusion peptide. This M latch is fastened at an earlier stage, during maturation at acidic pH in the trans-Golgi network. At a later stage, to initiate infection in response to acidic pH in the late endosome, M releases the latch and exposes the fusion peptide. Thus, M serves as a multistep chaperone of E to control the conformational changes accompanying maturation and infection. These pH-sensitive interactions could serve as targets for drug discovery

Direct and Relative Effects of the Import Tariff: Estimation Using the Chinese Industrial Level Data

The importing country usually imposes heterogeneous import tariff rates based on the national origins of the products. Reducing the tariff rates on the products from one origin country not only increases the imports from this country, but also decreases the imports from the other trade partners of the importing country. (Direct and relative effects of the import tariff) This paper constructs a variation of the conventional gravity model to analyze the direct and relative effects of the import tariff on international trade flows at the industrial level. Based on our theoretical framework, we compute a new indicator to measure the relative effect and estimate both effects using the Chinese industrial level data. Our empirical findings are consistent with our theoretical predictions: (i) if the tariff rates are reduced towards one origin country, the importing country will import more from this country but reduce the imports from the other origins; (ii) the relative effect is more effective at the industry or country where the importing penetration ratio is relatively high; and (iii) omission of the import penetration ratio will lead to the underestimation of the effects of the multilateral resistance terms on trade performances. Our research contributes to the existing literature by introducing a manipulable method to compute the direct and relative effects of the trade cost at the industrial level, which takes the heterogeneity among industries and countries into accoun

Direct and Relative Effects of the Import Tariff: Method and Application Using the Industrial Level Data

The importing country usually imposes heterogeneous import tariff rates based on the national origins of the products. Reducing the tariff rates on the products from one origin country not only increases the import flows from this country, but also decreases the import flows from the other trade partners of the importing country. (Direct and relative effects of the import tariff) This paper constructs a variation of the conventional gravity model to analyze the direct and relative effects of the import tariff on international trade flows at the industrial level. Based on our theoretical framework, we compute a new indicator to measure the relative effect and estimate both effects using the Chinese industrial level data. Our empirical findings are consistent with our theoretical predictions: (i) if the tariff rates are reduced towards one origin country, the importing country will import more from this country but reduce the imports from the other origins; (ii) the relative effect is more effective at the industry or country where the importing penetration ratio is relatively high; and (iii) omission of the import penetration ratio will lead to the underestimation of the effects of the multilateral resistance terms on trade performances. Our research contributes to the existing literature by introducing a manipulable method to compute the direct and relative effects of the trade cost at the industrial level, which takes the heterogeneity among industries and countries into account

Direct and Relative Effects of the Import Tariff: Estimation Using the Chinese Industrial Level Data

The importing country usually imposes heterogeneous import tariff rates based on the national origins of the products. Reducing the tariff rates on the products from one origin country not only increases the imports from this country, but also decreases the imports from the other trade partners of the importing country. (Direct and relative effects of the import tariff) This paper constructs a variation of the conventional gravity model to analyze the direct and relative effects of the import tariff on international trade flows at the industrial level. Based on our theoretical framework, we compute a new indicator to measure the relative effect and estimate both effects using the Chinese industrial level data. Our empirical findings are consistent with our theoretical predictions: (i) if the tariff rates are reduced towards one origin country, the importing country will import more from this country but reduce the imports from the other origins; (ii) the relative effect is more effective at the industry or country where the importing penetration ratio is relatively high; and (iii) omission of the import penetration ratio will lead to the underestimation of the effects of the multilateral resistance terms on trade performances. Our research contributes to the existing literature by introducing a manipulable method to compute the direct and relative effects of the trade cost at the industrial level, which takes the heterogeneity among industries and countries into accoun

Computation with Advice

Computation with advice is suggested as generalization of both computation with discrete advice and Type-2 Nondeterminism. Several embodiments of the generic concept are discussed, and the close connection to Weihrauch reducibility is pointed out. As a novel concept, computability with random advice is studied; which corresponds to correct solutions being guessable with positive probability. In the framework of computation with advice, it is possible to define computational complexity for certain concepts of hypercomputation. Finally, some examples are given which illuminate the interplay of uniform and non-uniform techniques in order to investigate both computability with advice and the Weihrauch lattice

Guaranteed quality isotropic surface remeshing based on uniformization

Surface remeshing plays a significant role in computer graphics and visualization. Numerous surface remeshing methods have been developed to produce high quality meshes. Generally, the mesh quality is improved in terms of vertex sampling, regularity, triangle size and triangle shape. Many of such surface remeshing methods are based on Delaunay refinement. In particular, some surface remeshing methods generate high quality meshes by performing the planar Delaunay refinement on the conformal uniformization domain. However, most of these methods can only handle topological disks. Even though some methods can cope with high-genus surfaces, they require partitioning a high-genus surface into multiple simply connected segments, and remesh each segment in the parameterized domain. In this work, we propose a novel surface remeshing method based on uniformization theorem using dynamic discrete Yamabe flow and Delaunay refinement, which is capable of handling surfaces with complicated topologies, without the need of partitioning. The proposed method has the following merits: Dimension deduction, it converts all 3D surface remeshing to 2D planar meshing; Theoretic rigor, the existence of the constant curvature measures and the lower bound of the corner angles of the generated meshes can be proven. Experimental results demonstrate the efficiency and efficacy of our proposed method

Assessment of causal association between differentiated thyroid cancer and disordered serum lipid profile: a Mendelian randomization study

BackgroundResearch has shown that the disordered serum lipid profile may be associated with the risk of differentiated thyroid cancer (DTC). Whether this association reflect causal effect is still unclear. The aim of this study was to evaluate the causality of circulating lipoprotein lipids on DTC.MethodsMendelian randomization (MR) analysis was conducted to evaluate the relationship between the circulating lipoprotein lipids and DTC risk using single-nucleotide polymorphisms (SNPs) from a genome-wide association (GWA) study containing a high-incidence Italian population of 690 cases samples with DTC and 497 controls.ResultsUnivariate and multivariate mendelian randomization analysis demonstrated that ‘total cholesterol’, ‘HDL cholesterol’, ‘apolipoprotein B’ and ‘ratio of apolipoprotein B to apolipoprotein A1’ were correlated with DTC. According to sensitivity analysis, our results were reliable. Furthermore, multivariate analysis revealed that there is no causative association between DTC and any of the many cause factors when they interact with one another, suggesting that there was a deep interaction between the four factors, which could affect each other. Finally, the mechanism of the related effects each other as well as the target genes with significant SNP regulatory effects in DTC was explored by conducting functional enrichment analysis and constructing the regulatory networks.ConclusionsWe obtained four exposure factors (total cholesterol, HDL cholesterol, apolipoprotein B and ratio of apolipoprotein B to apolipoprotein A1) closely related to DTC, which laid a theoretical foundation for the treatment of DTC

Uncovering and Quantifying Social Biases in Code Generation

With the popularity of automatic code generation tools, such as Copilot, the study of the potential hazards of these tools is gaining importance. In this work, we explore the social bias problem in pre-trained code generation models. We propose a new paradigm to construct code prompts and successfully uncover social biases in code generation models. To quantify the severity of social biases in generated code, we develop a dataset along with three metrics to evaluate the overall social bias and fine-grained unfairness across different demographics. Experimental results on three pre-trained code generation models (Codex, InCoder, and CodeGen) with varying sizes, reveal severe social biases. Moreover, we conduct analysis to provide useful insights for further choice of code generation models with low social bias. (This work contains examples that potentially implicate stereotypes, associations, and other harms that could be offensive to individuals in certain social groups.

Spherical representation and polyhedron routing for load balancing in wireless sensor networks

Abstract—In this paper we address the problem of scalable and load balanced routing for wireless sensor networks. Motivated by the analog of the continuous setting that geodesic routing on a sphere gives perfect load balancing, we embed sensor nodes on a convex polyhedron in 3D and use greedy routing to deliver messages between any pair of nodes with guaranteed success. This embedding is known to exist by the Koebe-Andreev-Thurston Theorem for any 3-connected planar graphs. In our paper we use discrete Ricci flow to develop a distributed algorithm to compute this embedding. Further, such an embedding is not unique and differs from one another by a Möbius transformation. We employ an optimization routine to look for the Möbius transformation such that the nodes are spread on the polyhedron as uniformly as possible. We evaluated the load balancing property of this greedy routing scheme and showed favorable comparison with previous schemes. I