On the prevalence of elliptic and genus one fibrations among toric hypersurface Calabi-Yau threefolds

We systematically analyze the fibration structure of toric hypersurface Calabi-Yau threefolds with large and small Hodge numbers. We show that there are only four such Calabi-Yau threefolds with $h^{1, 1} \geq 140$ or $h^{2, 1} \geq 140$ that do not have manifest elliptic or genus one fibers arising from a fibration of the associated 4D polytope. There is a genus one fibration whenever either Hodge number is 150 or greater, and an elliptic fibration when either Hodge number is 228 or greater. We find that for small $h^{1, 1}$ the fraction of polytopes in the KS database that do not have a genus one or elliptic fibration drops exponentially as $h^{1,1}$ increases. We also consider the different toric fiber types that arise in the polytopes of elliptic Calabi-Yau threefolds.Comment: 37 pages, 8 figures; v2: references adde

Merit and Mothering: Women and Social Welfare in Taiwanese Buddhism

This is a publisher's version of an article published in The Journal of Asian Studies in 1998. The offprint is posted here in accordance with existing publisher policy, or by special permission via correspondence.tru

Fibration structure in toric hypersurface Calabi-Yau threefolds

We find through a systematic analysis that all but 29,223 of the 473.8 million 4D reflexive polytopes found by Kreuzer and Skarke have a 2D reflexive subpolytope. Such a subpolytope is generally associated with the presence of an elliptic or genus one fibration in the corresponding birational equivalence class of Calabi-Yau threefolds. This extends the growing body of evidence that most Calabi-Yau threefolds have an elliptically fibered phase.Comment: 14 pages, 4 figures; v2: minor changes, comments adde

Comparing elliptic and toric hypersurface Calabi-Yau threefolds at large Hodge numbers

We compare the sets of Calabi-Yau threefolds with large Hodge numbers that are constructed using toric hypersurface methods with those can be constructed as elliptic fibrations using Weierstrass model techniques motivated by F-theory. There is a close correspondence between the structure of "tops" in the toric polytope construction and Tate form tunings of Weierstrass models for elliptic fibrations. We find that all of the Hodge number pairs ($h^{1, 1},h^{2, 1}$) with $h^{1,1}$ or $h^{2, 1}\geq 240$ that are associated with threefolds in the Kreuzer-Skarke database can be realized explicitly by generic or tuned Weierstrass/Tate models for elliptic fibrations over complex base surfaces. This includes a relatively small number of somewhat exotic constructions, including elliptic fibrations over non-toric bases, models with new Tate tunings that can give rise to exotic matter in the 6D F-theory picture, tunings of gauge groups over non-toric curves, tunings with very large Hodge number shifts and associated nonabelian gauge groups, and tuned Mordell-Weil sections associated with U(1) factors in the corresponding 6D theory.Comment: 92 pages, 7 figures; v6: cleaned up errors in reference

Mirror symmetry and elliptic Calabi-Yau manifolds

We find that for many Calabi-Yau threefolds with elliptic or genus one fibrations mirror symmetry factorizes between the fiber and the base of the fibration. In the simplest examples, the generic CY elliptic fibration over any toric base surface $B$ that supports an elliptic Calabi-Yau threefold has a mirror that is an elliptic fibration over a dual toric base surface $\tilde{B}$ that is related through toric geometry to the line bundle $-6K_B$. The Kreuzer-Skarke database includes all these examples and gives a wide range of other more complicated constructions where mirror symmetry also factorizes. Since recent evidence suggests that most Calabi-Yau threefolds are elliptic or genus one fibered, this points to a new way of understanding mirror symmetry that may apply to a large fraction of smooth Calabi-Yau threefolds. The factorization structure identified here can also apply for Calabi-Yau manifolds of higher dimension.Comment: 30 pages, 6 figures; v2: corrected Table 1, added reference

Experimental and Numerical Investigations on Dynamic Characteristics for Piezoceramic Bimorphs

Piezoceramic bimorph structures have been widely used in recent years as they combine the advantages of different materials. Two thin layers of piezoelectric ceramic are bonded together with the central layer of metal and are electrically connected in parallel and series. The structure produces large strokes with relatively low voltage because of its special bimorph concept. It is necessary to investigate the resonant characteristics of the bimorphs theoretically and experimentally to facilitate the industrial applications. In this study, three experimental techniques are employed to access the resonant characteristics of the bimorphs. These experimental methods are the electronic speckle pattern interferometry (ESPI), laser Doppler vibrometer (LDV), and impedance analysis. Finally, numerical computations based on the finite element method are presented and compared with the experimental measurements. Good agreements of resonant frequencies and mode shapes are obtained from the experimental and numerical results

The Optimal Pricing Strategy of a Mobile Payment Service in a Two-sided Market

Acknowledging the high penetration rate of mobile devices, mobile payment is currently a hot topic and is expected to reach the tipping point of rapid growth. For such a nascent market, how to run a successful mobile payment platform remains unanswered. Therefore, we devote this study to investigate the pricing strategy of proximity mobile payment. Mobile payment serves as a two-sided platform connecting merchants and customers. By leveraging the emergent mobile payment knowledge, we present a game-theoretic model featuring network externality. In the short run, we find the platform will have incentives to apply “divide and conquer” strategy by subsidizing customers to adopt the mobile payment service at the beginning of the business. After the ignition, the platform then becomes profitable by charging per transaction fee from the merchants. In the long run, the subsidization strategy is suggested to be applied when the bank is not taking too much processing fee and leaves sufficient market share to the mobile payment platform. In terms of contributions to practice, this study offers a step forward of method to identify this promising market for mobile payment executives, financial institutes and all others ecosystem

The Carnegie-Irvine Galaxy Survey. III. The Three-Component Structure of Nearby Elliptical Galaxies

Motivated by recent developments in our understanding of the formation and evolution of massive galaxies, we explore the detailed photometric structure of a representative sample of 94 bright, nearby elliptical galaxies, using high-quality optical images from the Carnegie-Irvine Galaxy Survey. The sample spans a range of environments and stellar masses, from M* = 10^{10.2} to 10^{12.0} solar mass. We exploit the unique capabilities of two-dimensional image decomposition to explore the possibility that local elliptical galaxies may contain photometrically distinct substructure that can shed light on their evolutionary history. Compared with the traditional one-dimensional approach, these two-dimensional models are capable of consistently recovering the surface brightness distribution and the systematic radial variation of geometric information at the same time. Contrary to conventional perception, we find that the global light distribution of the majority (>75%) of elliptical galaxies is not well described by a single Sersic function. Instead, we propose that local elliptical galaxies generically contain three subcomponents: a compact (R_e < 1 kpc) inner component with luminosity fraction f ~ 0.1-0.15; an intermediate-scale (R_e ~ 2.5 kpc) middle component with f ~ 0.2-0.25; and a dominant (f = 0.6), extended (R_e ~ 10 kpc) outer envelope. All subcomponents have average Sersic indices n ~ 1-2, significantly lower than the values typically obtained from single-component fits. The individual subcomponents follow well-defined photometric scaling relations and the stellar mass-size relation. We discuss the physical nature of the substructures and their implications for the formation of massive elliptical galaxies.Comment: To appear in The Astrophysical Journal; 36 pages, 2 tables, 38 figures; For the full resolution version, see: http://users.obs.carnegiescience.edu/shuang/PaperIII.pdf ; For the atlas of all selected models, see http://users.obs.carnegiescience.edu/shuang/AppendixE.pd