Large Counterpart Research Articles

Global solutions for 1D cubic defocusing dispersive equations: Part I

Abstract This article is devoted to a general class of one-dimensional NLS problems with a cubic nonlinearity. The question of obtaining scattering, global in time solutions for such problems has attracted a lot of attention in recent years, and many global well-posedness results have been proved for a number of models under the assumption that the initial data are both small and localized. However, except for the completely integrable case, no such results have been known for small but not necessarily localized initial data. In this article, we introduce a new, nonperturbative method to prove global well-posedness and scattering for $L^2$ initial data which are small and nonlocalized. Our main structural assumption is that our nonlinearity is defocusing. However, we do not assume that our problem has any exact conservation laws. Our method is based on a robust reinterpretation of the idea of Interaction Morawetz estimates, developed almost 20 years ago by the I-team. In terms of scattering, we prove that our global solutions satisfy both global $L^6$ Strichartz estimates and bilinear $L^2$ bounds. This is a Galilean invariant result, which is new even for the classical defocusing cubic NLS.1 There, by scaling, our result also admits a large data counterpart.

Preliminary geological mapping with convolution neural network using statistical data augmentation on a 3D model

Airborne magnetic data are commonly processed and interpreted by geologists to produce preliminary geological maps of unexplored areas. Machine learning can partly fulfill this task rapidly and objectively as convolutional neural networks applied to image segmentation showed promising results in comparable applications. As these algorithms require a large and high-quality dataset to be trained, we developed an innovative geostatistical data augmentation workflow that uses a 3D conceptual lithological and magnetic susceptibility model as input. The workflow uses soft-constrained Multi-Point Statistics to create equiprobable synthetic 3D geological models and Sequential Gaussian Simulation to populate these models with a geologically meaningful magnetic susceptibility spatial distribution. Then, geophysical forward modeling is computed to get the airborne magnetic responses of the synthetic models, which are associated with their counterpart synthetic geological maps. We applied this workflow on a 3D model of the Malartic Mine area to obtain a large synthetic airborne magnetic and counterpart geological map dataset. Then, a Gated Shape Convolutional Network is trained on this dataset to perform a preliminary geological mapping. A semi-supervised approach using clustering on the feature maps from the trained network is also implemented. Testing the trained network on synthetic data and remote areas of similar geological context shows that the methodology is suitable for producing preliminary geological maps using airborne magnetic data. Notably, the clustering module shows a precise and adaptive segmentation of the magnetic anomalies into pertinent preliminary geological maps. The quality of the results empirically validates our data augmentation method. Our method allows producing geological maps by training a convolutional neural network using an area where a detailed geological and petrophysical 3D model exists and then permits applying the pre-trained model in new areas of the same geological context, where only airborne magnetic data is available.

Size effects of mechanical properties of nanohoneycomb with multiple surface orientations

Nanostructures and nanomaterials have been studied thoroughly due to their remarkable properties. With various sizes and shapes, they serve as highly functional sensors in nanoelectromechanical systems (NEMS), noninvasive medical diagnostic devices or drug delivers. Although the importance of surfaces has been recognized when it comes to the nanoscale, few researchers investigate nanostructures with multiple surface orientations. In this work, we propose a two-surface theoretical model for nanohoneycombs and verify the model by conducting molecular dynamics (MD) simulations on regular hexagonal Al nanohoneycombs with cell-wall thickness ranging from 5 nm to 30 nm. These numerical examples show excellent agreement with the proposed theory, proving the applicability of the two-surface model. The Al nanohoneycomb exhibits significant “positive” size dependence – it is 2.4 times stiffer compared with its large counterpart when the cell-wall thickness is 5.7 nm. In sum, this study improves the accuracy of the predicted in-plane Young's moduli of nanohoneycombs by taking differently oriented surfaces into account and considering more comprehensive deformation mechanisms. By investigating nanosized honeycomb structure in-depth and providing a more general theoretical model, we aim to improve the accuracy of predicted mechanical properties and provide a guide for the applicability of various models for honeycombs. Furthermore, this study can help exploit the full potential of various nanoporous structures, not restricted to nanohoneycombs.

Multi-objective optimization of a small sized solar PV-T water collector using controlled elitist NSGA-II coupled with TOPSIS

Small-sized solar photovoltaic thermal (PV-T) collector can achieve better overall performance due to less aperture plane heat losses and the possibility of concentrating more radiant flux per unit aperture area compared to their large counterpart designs. Despite its potential, studies on its performance optimization have not yet been explored. This study aims to perform a multi-objective optimization of the performance of a small-sized PV-T water collector with channel type absorber design by using a two-step procedure i.e., implementation of Non dominated sorting genetic algorithm (NSGA-II) followed by a decision making method i.e., a technique for order preference by similarity to ideal solution (TOPSIS). Based on the Taguchi orthogonal array design for three control parameters i.e., mass flow rate, inlet temperature, and inclination angle, an experimental campaign is undertaken. The design space created on the basis of Taguchi design of experiment is used to conduct a total 16 number of experiments. An analysis of variance is carried out to obtain the significant design and operating parameters controlling the collector performance, which are used to fit the objective function equations for both thermal and electrical efficiency. A multi objective optimization strategy is then developed by a variant of NSGA-II to simultaneously optimize its average thermal and electrical efficiencies. From the obtained Pareto fronts, the most optimal solution is obtained by using TOPSIS method. The highest thermal and electrical efficiency of 82.55% and 10.45% is obtained under an optimal mass flow rate of 0.02 kg/s, inlet temperature 32 °C and inclination angle 38.88°. The influence of solar radiation on its optimized performance demonstrates a little less higher thermal efficiency of 81.05% and electrical efficiency of 11.43% obtained at a radiation of 700 W/m2. On experimental verification of the optimized performance, the highest thermal and electrical efficiency is obtained within an agreement of ± 3.51% and ± 6.9%, respectively. The present optimized efficiency values are higher compared to that of a typical experimental day with un-optimized input conditions and also higher than some of the recent published papers.

Variation of Green Synthesis Techniques in Fabrication of Zinc Oxide Nanoparticles – A Mini Review

The field of nanotechnology has been one of the major focus of research for scientists across the world. This field deals with the production and usage of nanoscale materials. The popularity of nanotechnology is due to its unique properties that cannot be found in its large counterpart. In these recent years, zinc oxide nanoparticles (ZnO NPs) emerged as an important ceramic material that can be utilized across various fields such as medicine, cosmetics, textiles, wastewater treatment and many others. The fabrication of ZnO NPs can proceed through three major pathways which are physical, chemical and green synthesis. Among these synthesis method, green synthesis is preferable as it is more environmentally friendly. In this review, we summarize the various techniques of green synthesis in fabrication of ZnO NPs.

Miniature Hollow Gold Nanorods with Enhanced Effect for In Vivo Photoacoustic Imaging in the NIR-II Window.

The miniaturization of gold nanorods exhibits a bright prospect for intravital photoacoustic imaging (PAI) and the hollow structure possesses a better plasmonic property. Herein, miniature hollow gold nanorods (M-AuHNRs) (≈46nm in length) possessing strong plasmonic absorbance in the second near-infrared (NIR-II) window (1000-1350nm) are developed, which are considered as the most suitable range for the intravital PAI. The as-prepared M-AuHNRs exhibit 3.5 times stronger photoacoustic signal intensity than the large hollow Au nanorods (≈105nm in length) at 0.2 optical density under 1064nm laser irradiation. The in vivo biodistribution measurement shows that the accumulation in tumor of miniature nanorods is twofold as high as that of the large counterpart. After modifying with a tumor-targeting molecule and fluorochrome, in living tumor-bearing mice, the M-AuHNRs group gives a high fluorescence intensity in tumors, which is 3.6-fold that of the large ones with the same functionalization. Moreover, in the intravital PAI of living tumor-bearing mice, the M-AuHNRs generate longer-lasting and stronger photoacoustic signal than the large counterpart in the NIR-II window. Overall, this study presents the fabrication of M-AuHNRs as a promising contrast agent for intravital PAI.

Proxy Painting

For archaeologists, it is often desirable to present statues in their original material and coloration. With projection mapping, real-world surfaces are augmented by digital content to create compelling alterations of the scene’s visual appearance without actually altering or even damaging the object. While there are frequent advances in projection quality, content creation is still a challenging and often unintuitive task, especially for non-experts. In our system, we combine the advantages of digital content creation, such as rapid prototyping, with the convenience of an analog workflow. Users paint on smaller versions of the projection mapping target, employing real-world brushes and pencils, while the results are presented live on its large counterpart. We further demonstrate the integration of our system into a state-of-art game engine. By leveraging a powerful rendering and material workflow, we make creating compelling materials and lighting situations an intuitive experience.

Yet another note on the arithmetic-geometric mean inequality

It was shown by E. Gluskin and V.D. Milman in [GAFA Lecture Notes in Math. 1807, 2003] that the classical arithmetic-geometric mean inequality can be reversed (up to a multiplicative constant) with high probability, when applied to coordinates of a point chosen with respect to the surface unit measure on a high-dimensional Euclidean sphere. We present here two asymptotic refinements of this phenomenon in the more general setting of the surface probability measure on a high-dimensional $\ell_p$-sphere, and also show that sampling the point according to either the cone probability measure on $\ell_p$ or the uniform distribution on the ball enclosed by $\ell_p$ yields the same results. First, we prove a central limit theorem, which allows us to identify the precise constants in the reverse inequality. Second, we prove the large deviations counterpart to the central limit theorem, thereby describing the asymptotic behavior beyond the Gaussian scale, and identify the rate function.

Gaussian fluctuations for high-dimensional random projections of $\ell_{p}^{n}$-balls

In this paper, we study high-dimensional random projections of $\ell_{p}^{n}$-balls. More precisely, for any $n\in\mathbb{N}$ let $E_{n}$ be a random subspace of dimension $k_{n}\in\{1,\ldots,n\}$ and $X_{n}$ be a random point in the unit ball of $\ell_{p}^{n}$. Our work provides a description of the Gaussian fluctuations of the Euclidean norm $\|P_{E_{n}}X_{n}\|_{2}$ of random orthogonal projections of $X_{n}$ onto $E_{n}$. In particular, under the condition that $k_{n}\to\infty$ it is shown that these random variables satisfy a central limit theorem, as the space dimension $n$ tends to infinity. Moreover, if $k_{n}\to\infty$ fast enough, we provide a Berry–Esseen bound on the rate of convergence in the central limit theorem. At the end, we provide a discussion of the large deviations counterpart to our central limit theorem.

Identifying a Z′ behind b→sℓℓ anomalies at the LHC

Recent $b\to s\ell\ell$ anomalies may imply the existence of a new $Z'$ boson with left-handed $Z'bs$ and $Z'\mu\mu$ couplings. Such a $Z'$ may be directly observed at LHC via $b \bar s \to Z' \to \mu^+\mu^-$, and its relevance to $b\to s\ell\ell$ may be studied by searching for the process $gs \to Z'b \to \mu^+\mu^- b$. In this paper, we analyze the capability of the 14 TeV LHC to observe the $Z'$ in the $\mu^+ \mu^-$ and $\mu^+\mu^- b$ modes based on an effective model with major phenomenological constraints imposed. We find that both modes can be discovered with 3000 fb$^{-1}$ data if the $Z'bs$ coupling saturates the latest $B_s-\bar B_s$ mixing limit from UTfit at around $2\sigma$. Besides, a tiny right-handed $Z'bs$ coupling, if it exists, opens up the possibility of a relatively large left-handed counterpart, due to cancellation in the $B_s-\bar B_s$ mixing amplitude. In this case, we show that even a data sample of $\mathcal{O}(100)$ fb$^{-1}$ would enable discovery of both modes. We further study the impact of a $Z'bb$ coupling as large as the $Z'bs$ coupling. This scenario enables discovery of the $Z'$ in both modes with milder effects on the $B_s-\bar B_s$ mixing, but obscures the relevance of the $Z'$ to $b \to s\ell\ell$. Discrimination between the $Z'bs$ and $Z'bb$ couplings may come from the production cross section for the $Z'b\bar{b}$ final state. However, we do not find the prospect for this to be promising.

Smart Derivative Contracts (Detaching Transactions from Counterparty Credit Risk: Specification, Parametrisation, Valuation)

In this note we describe a smart derivative contract with a fully deterministic termination to remove many of the inefficiencies in collateralized OTC transactions. The automatic termination procedure embedded in the smart contracts replaces the counterparty default by an option right of the counterparty. The application of smart contracts to cure issues in xVAs has been described before, see Morini et. al. (2015, 2017). However, a direct implementation of an OTC derivative as a smart contract may come with its own issues: * If the smart contract is implemented on a crypto-currency blockchain it will introduce a currency conversion risk. * If the smart contract has an automatic termination in case of insufficient wallet amounts, the contract essentially contains a bilateral American option. Both counterparts can willingly terminate the contract by emptying the wallet. This would render the contract useless. In this note we will fully describe the terms of a smart contract to replace a collateralized OTC transaction. We introduce a penalty payment to modify the American option right in the contract. The penalty and the excess amount in the wallet can be seen as a combination of default fund contribution and initial margin, inducing a per-contract termination probability. Hence, each contract come with its own termination probability (corresponding to the default probability). Based on this, ratings could be assigned on a per-contract basis. Such smart contracts are also interesting with respect to the mathematical theory of systemic risk, since each contract represents an individual counterparty, increasing the numbers of individual counterparties in the whole system and possibly justifying the application of mean filed theory (compared to a setup with a large central counterpart (CCP)).

Thermoelectric Properties of p-Type Clathrate Ba8.0Ga15.9ZnySn30.1 Single Crystals with Various Carrier Concentrations

To match the excellent performance of n-type type-VIII clathrate Ba8Ga16Sn30 single crystals in thermoelectric (TE) generator design, synthesizing a large size p-type counterpart with a high TE figure of merit ZT continues to be a challenge for many years. In this work, we obtained 7-mm-diameter single crystals of Zn-substituted type-VIII clathrate Ba8Ga16Sn30 (Zn-BGS) with various carrier concentrations by Ga-flux method. Though the actual substituted compositions of the single crystals Ba8Ga15.9ZnySn30.1 (y = 0–0.019) are much lower than the nominal ones, the Zn atoms work as a “spur” and effectively suppress the nucleation rate of BGS in the Ga-flux, which is vital to achieving a similar large size crystal with the n-type counterpart. The y = 0.006 and 0.007 crystals share nearly the same or a slightly lower value of resistivity with a pristine crystal in the whole temperature. However, the Hall coefficient measurement revealed that Zn substitution triggers a profound transition from a “low-carrier-concentration high-carrier-mobility” regime to a “high-carrier-concentration low-carrier-mobility” one in p-type BGS. As a consequence, both the Seebeck coefficient and thermal conductivity benefit from the relief of the negative impact of minority carrier by shifting the “trigger temperature” of intrinsic excitation to a higher temperature. Figure of merit ZTs of 0.97 and 1.07 are observed for x = 0.006, 0.007 at 500 K, which are more than 25% and 40% higher than the figure of merit for pristine BGS at the same temperature zone, respectively. The improvement demonstrates the potential of making TE modules from n- and p-type single crystal BGS for waste heat recovery at medium temperatures.

Exploring the surface morphology of developing wheat starch granules by using Atomic Force Microscopy

AbstractWheat starch granules from 7, 14, 21, 28, 35, 42, and 49 days after anthesis (DAA) were imaged using AFM. Starches were scanned in their native form as well as following exposure to iodine vapour in‐situ at 100% humidity. Starch at 7 DAA exhibited only one granule population, while starches at other maturities had two size populations. Starches from all stages of maturation exhibited blocklet structures. Larger fuzzy blocklets were observed at early stages while they became smaller and less fuzzy at subsequent stages of maturity. Furthermore, at all stages, small granules had larger fuzzy blocklets and higher surface roughness than the large granule counterpart; however the surface roughness of both small and large granule fractions decreased gradually with maturation. Amorphous growth ring of starch granules with ∼1 × 1 µm to ∼3 × 6 µm size islands were also observed. In‐situ iodine exposure demonstrated that iodine interacted with glucan polymers in the amorphous background first and then spread over to polymers on top of blocklets. Iodine‐glucan polymer interaction further increased the surface roughness.

IDENTIFYING CONTAGION RISK IN THE INTERNATIONAL BANKING SYSTEM: AN EXTREME VALUE THEORY APPROACH

ABSTRACTIn this article, we use the extreme value theory framework to analyse contagion risk across the international banking system. We test for the likelihood that an extreme shock affecting a major, systemic global bank would also affect another large local or foreign counterpart, and vice versa. Our results reveal several key trends among major global banks: contagion risk among banks exhibits ‘home bias’, individual banks are affected differently by idiosyncratic shocks to their major counterparts and banks are affected differently by common shocks to the real economy or financial markets. In general, bank soundness seems more susceptible to common (macro and market) shocks when the global environment is turbulent; this may have important implications for global financial stability especially during stressful periods. Not surprisingly, our findings also suggest that bank contagion risk has risen over time, which emphasizes the need for continuing collaboration on cross‐border supervision and crisis management. Copyright © 2012 John Wiley & Sons, Ltd.

Foreign Direct Investment, Endogenous Tariffs, and Preferential Trade Agreements

Abstract This paper examines the complementarity between international trade and investment policies, and argues that preferential trade agreements may be a particularly effective means for harnessing the tariff liberalizing potential of foreign direct investment. A simple two country model demonstrates that export-platform foreign investment induces unilateral tariff liberalization by the investment-source country, suggesting that international capital mobility may substitute partially for multilateral forums such as the WTO in achieving efficient tariffs. A multi-country extension of the model in which countries can compete for foreign investors via subsidies then develops an efficiency argument in favor of discriminatory tariff allowances such as Article XXIV of the GATT or the Generalized System of Preferences. When small countries can earn preferential tariff treatment from a large trading counterpart by encouraging local export-platform investment (or by discouraging import competing investment), the equilibrium tariff level will be lower when discriminatory tariffs are possible rather than when they are not.

Foreign Direct Investment, Endogenous Tariffs, and Preferential Trade Agreements.

This paper examines the complementarity between international trade and investment policies. A simple two country model demonstrates that export-platform FDI induces unilateral tariff liberalization by the FDI-source country, suggesting that international capital mobility may substitute partially for multilateral forums such as the WTO in achieving efficient tariffs. A multi-country extension of the model in which countries can compete for FDI via investment subsidies then develops an efficiency argument in favor of discriminatory tariff allowances such as GATT Article XXIV or Generalized Systems of Preferences. When small countries can earn preferential tariff treatment from a large trading counterpart by encouraging local export-platform FDI, the equilibrium aggregate FDI level will be higher and the tariff level lower when discriminatory tariffs are possible than when they are not.

On the strong discontinuity approach in finite deformation settings

AbstractTaking the strong discontinuity approach as a framework for modelling displacement discontinuities and strain localization phenomena, this work extends previous results in infinitesimal strain settings to finite deformation scenarios.By means of the strong discontinuity analysis, and taking isotropic damage models as target continuum (stress–strain) constitutive equation, projected discrete (tractions–displacement jumps) constitutive models are derived, together with the strong discontinuity conditions that restrict the stress states at the discontinuous regime. A variable bandwidth model, to automatically induce those strong discontinuity conditions, and a discontinuous bifurcation procedure, to determine the initiation and propagation of the discontinuity, are briefly sketched. The large strain counterpart of a non‐symmetric finite element with embedded discontinuities, frequently considered in the strong discontinuity approach for infinitesimal strains, is then presented. Finally, some numerical experiments display the theoretical issues, and emphasize the role of the large strain kinematics in the obtained results. Copyright © 2003 John Wiley & Sons, Ltd.

Size-dependent intracellular immunotargeting of therapeutic cargoes into endothelial cells

AbstractCell-selective intracellular targeting is a key element of more specific and safe enzyme, toxin, and gene therapies. Endothelium poorly internalizes certain candidate carriers for vascular immunotargeting, such as antibodies to platelet endothelial cell adhesion molecule 1 (PECAM–1). Conjugation of poorly internalizable antibodies with streptavidin (SA) facilitates the intracellular uptake. Although both small and large (100-nm versus 1000-nm diameter) anti-PECAM/SA–beta galactosidase (SA–β-gal) conjugates bound selectively to PECAM-expressing cells, only small conjugates showed intracellular accumulation of active β-gal. To study whether size of the conjugates controls the uptake, a series of anti-PECAM/SA and anti-PECAM/bead conjugates ranging from 80 nm to 5 µm in diameter were produced. Human umbilical vein endothelial cells and PECAM-transfected mesothelioma cells internalized 80- to 350-nm anti-PECAM conjugates, but not conjugates larger than 500 nm. Further, size controls intracellular targeting of active therapeutic cargoes in vitro and in vivo. Small anti-PECAM/DNA conjugates transfected target cells in culture 5-fold more effectively than their large counterpart (350- versus 4200-nm diameter). To evaluate the practical significance of the size-controlled subcellular addressing, we coupled glucose oxidase (GOX) to anti-PECAM and antithrombomodulin. Both types of conjugates had equally high pulmonary uptake after intravenous injection in mice, yet only small (200- to 250-nm), not large (600- to 700-nm), GOX conjugates caused profound oxidative vascular injury in the lungs, presumably owing to intracellular generation of H2O2. Thus, engineering of affinity carriers of specific size permits intracellular delivery of active cargoes to endothelium in vitro and in vivo, a paradigm useful for the targeting of drugs, genes, and toxins.

The Impact of Bank Structure on Small Business and Small Farm Lending

This paper empirically explores the impact of bank size, holding company affiliation and the degree of branching on small business and farm lending through a conceptual analysis encompassing private information asymmetries inherent in these bank dependent borrowers. The study expands the literature by removing the influence of capital constraints in bank dependent lending through comparing real estate secured to non real estate loans in a reduced form model. Furthermore, it encompasses an allocation analysis over bank dependent loans, its large loan counterpart and other assets. Overall the findings indicate that not only small banks, but instate and more particularly one bank holding company banks devote more of their assets to small business and farm loans. Banks owned by out-of-state holding companies do not. Low to moderately branched banks are also active in these markets. In this respect the smaller, more simply structured bank may possess a relative advantage in the bank dependent loan market arising from the capacity to mitigate acute informational asymmetries.

Approximations and upper bounds on probabilities of large deviations in the problem of ruin within finite time

Abstract In the framework of Andersen's risk model, a new asymptotic expression and upper bounds on probabilities of ruin after time t(u) ≫ and before time 0 < t(u) ≪ , as the initial risk reserve u increases to infinity, are suggested. This result complements the classical normal-type approximation for the probability of ruin within finite time and is designed as its large deviations counterpart. The main technical device of the paper (see Section 3), which is of independent interest, are the upper bounds and the asymptotic expressions for the probabilities of large deviations of the stopped random walks, developed under low moment conditions.