pinecone/core-2020-05-10-deduplication huggingface dataset:
Deciphering the libor and euribor spreads during the subprime crisis

This paper investigates the key role played by different factors, such as the use of Asset Backed Commercial Paper as collaterals in the short-term debt market, credit risk and the injection of liquidity by Central Banks through so-called unconventional measures, on the persistent spread during the subprime crisis bet. The empirical analysis shows that, in addition to credit risk, a relevant variable for explaining the interbank rate dynamics is the outstanding volume in the Asset Backed Commercial Paper market. In short, the large spread observed in the market is explained by the inter-relationship between collateralized short-term debt markets and the unsecured interbank market. It is also shown that Central Bank “non-conventional” intervention variables are relevant in affecting the spread both in the long-run but mostly in the short-run
Origin of salinity in a multilayered aquifer with high salinization vulnerability

International audienceThe Kaluvelly watershed is a coastal area (Tamil Nadu, India) where water abstraction has resulted in a dramatic fall in the level of the water table and a piezometric depression in the most exploited aquifer, the Vanur aquifer. In addition, intensification/mechanization of agriculture may have affected the quality of recharge water. An initial hydrodynamic study showed that the Vanur aquifer is highly vulnerable to salinization due to potential seawater intrusion, and our aim was to determine the source of salinity recorded in the groundwater of this multilayered aquifer. Our approach involved the use of existing boreholes and of a moderate number of samples, with the aim of developing appropriate water resource management techniques. Major elements, 18O/16O, 2H/1H, and 87Sr/86Sr ratios were measured in rainwater, surface water and groundwater collected during five sampling campaigns over a two-year period. Geochemical data indicate that the Vanur aquifer is recharged and that small mixings between aquifers fluctuate according to monsoon intensity. There was no evidence of seawater intrusion. The range of recorded salinity originated mainly from water-rock interaction but a disconnection of some deeper parts of the aquifer was apparent. Strontium isotopic ratios in the recharge area suggest an anthropogenic influence, possibly related to fertilizer use. A high SO4/Cl ratio was observed in the aquifer; in the deeper parts, the influence of a formation containing lignite is hypothesized, whereas near the surface, sulphate may partly originate from fertilizer use and fossil fuel combustion. Water isotopic data suggest that the origin of precipitation in this region has been unchanged for several hundreds or thousands of year
Secure Auctions without Cryptography

International audienceAn auction is a simple way of selling and buying goods. Modern auction protocols often rely on complex cryptographic operations to ensure manifold security properties such as bidder-anonymity or bid-privacy, non-repudiation, fairness or public verifiability of the result. This makes them difficult to understand for users who are not experts in cryptography. We propose two physical auction protocols inspired by Sako's cryptographic auction protocol. In contrast to Sako's protocol, they do not rely on cryptographic operations, but on physical properties of the manipulated mechanical objects to ensure the desired security properties. The first protocol only uses standard office material, whereas the second uses a special wooden box. We validate the security of our solutions using ProVerif
Left-Right Symmetry And Neutrino Stability

We consider a left-right symmetric model in which neutrinos acquire mass due to the spontaneous violation of both the gauged B−L and a global U(1) symmetry broken by the vacuum expectation value (VEV) of a gauge singlet scalar boson $\VEV{\sigma}$. For suitable choices of $\VEV{\sigma}$ consistent with all laboratory and astrophysical observations neutrinos will be unstable against majoron emission. All neutrino masses in the keV to MeV range are possible, since the expected neutrino decay lifetimes can be short enough to dilute their relic density below the cosmologically required level. A wide variety of possible new phenomena, associated to the presence of left-right symmetry and/or the global symmetry at the TeV scale, could therefore be observable, without conflict with cosmology. The latter includes the possibility of invisibly decaying higgs bosons, which can be searched at LEP, NLC and LHC
Sum-of-Squares approach to feedback control of laminar wake flows

A novel nonlinear feedback control design methodology for incompressible fluid flows aiming at the optimisation of long-time averages of flow quantities is presented. It applies to reduced-order finite-dimensional models of fluid flows, expressed as a set of first-order nonlinear ordinary differential equations with the right-hand side being a polynomial function in the state variables and in the controls. The key idea, first discussed in Chernyshenko et al. 2014, Philos. T. Roy. Soc. 372(2020), is that the difficulties of treating and optimising long-time averages of a cost are relaxed by using the upper/lower bounds of such averages as the objective function. In this setting, control design reduces to finding a feedback controller that optimises the bound, subject to a polynomial inequality constraint involving the cost function, the nonlinear system, the controller itself and a tunable polynomial function. A numerically tractable approach to the solution of such optimisation problems, based on Sum-of-Squares techniques and semidefinite programming, is proposed. To showcase the methodology, the mitigation of the fluctuation kinetic energy in the unsteady wake behind a circular cylinder in the laminar regime at Re=100, via controlled angular motions of the surface, is numerically investigated. A compact reduced-order model that resolves the long-term behaviour of the fluid flow and the effects of actuation, is derived using Proper Orthogonal Decomposition and Galerkin projection. In a full-information setting, feedback controllers are then designed to reduce the long-time average of the kinetic energy associated with the limit cycle. These controllers are then implemented in direct numerical simulations of the actuated flow. Control performance, energy efficiency, and physical control mechanisms identified are analysed. Key elements, implications and future work are discussed
Alternative reproductive tactics in snail shell-brooding cichlids diverge in energy reserve allocation

Life history theory predicts that the amount of resources allocated to reproduction should maximize an individual's lifetime reproductive success. So far, resource allocation in reproduction has been studied mainly in females. Intraspecific variation of endogenous energy storage and utilization patterns of males has received little attention, although these patterns may vary greatly between individuals pursuing alternative reproductive tactics (ARTs). ARTs are characterized by systematic variation of behavioral, physiological, and often morphological traits among same-sex conspecifics. Some individuals may rely on previously accumulated reserves, because of limited foraging opportunities during reproduction. Others may be able to continue foraging during reproduction, thus relying on reserves to a lesser extent. We therefore predicted that, if male tactics involve such divergent limitations and trade-offs within a species, ARTs should correspondingly differ in energy reserve allocation and utilization. To test this prediction, we studied short-term and long-term reserve storage patterns of males in the shell-brooding cichlid Lamprologus callipterus. In this species, bourgeois males investing in territory defense, courtship, and guarding of broods coexist with two distinct parasitic male tactics: (1) opportunistic sneaker males attempting to fertilize eggs by releasing sperm into the shell opening when a female is spawning; and (2) specialized dwarf males attempting to enter the shell past the spawning female to fertilize eggs from inside the shell. Sneaker males differed from other male types by showing the highest amount of accumulated short-term and long-term fat stores, apparently anticipating their upcoming adoption of the nest male status. In contrast, nest males depleted previously accumulated energy reserves with increasing nest holding period, as they invest heavily into costly reproductive behaviors while not taking up any food. This conforms to a capital breeder strategy. Dwarf males did not accumulate long-term fat stores at all, which they can afford due to their small behavioral effort during reproduction and their continued feeding activity, conforming to an income breeder strategy. Our data confirm that the resource storage patterns of males pursuing ARTs can diverge substantially, which adds to our understanding of the coexistence and maintenance of alternative reproductive patterns within species
Linear and quadratic static response functions and structure functions in Yukawa liquids

We compute linear and quadratic static density response functions of three-dimensional Yukawa liquids by applying an external perturbation potential in molecular dynamics simulations. The response functions are also obtained from the equilibrium fluctuations (static structure factors) in the system via the fluctuation-dissipation theorems. The good agreement of the quadratic response functions, obtained in the two different ways, confirms the quadratic fluctuation-dissipation theorem. We also find that the three-point structure function may be factorizable into two-point structure functions, leading to a cluster representation of the equilibrium triplet correlation function
Signal penalties induced by different types of optical filters in 100 Gbps PM-DQPSK based optical networks

Optical filters are crucial elements in optical communication networks. However, they seriously affect the signal quality, especially in the concatenation condition. In this paper, we study and simulate the signal penalties induced by five types of filters, including Butterworth, Gaussian, Bessel, Fiber Bragg Grating (FBG) and Fabry–Perot (F–P) filters, in order to optimize the optical network performance. Signal penalties, including both filter concatenation effect and filter induced in-band and out-band crosstalk, are analyzed by eye opening penalty (EOP) and Q-penalty. Simulation results show that the Butterworth filter performs best among these four types of filters. Total Q-penalty induced by a Butterworth filter-based demultiplexer/multiplexer pair, considering both filter concatenation effect and crosstalk, is lower than 0.5 dB, when the filter bandwidth is in the range of 42–46 GHz. Simulations done in a 100 Gbps PM-DQPSK optical network indicate that the permitted cascaded number is 14 and 10 with respect to the case of filters aligned and misaligned, respectively. Penalties induced by laser frequency shift are investigated and the performance of the 3rd-order Butterworth filter is compared to the 4th-order superGaussian filter. Finally, discussions of optical filter performances, including insertion loss, reconfigurability and programmability, are presented
Exploring, exploiting and evolving diversity of aquatic ecosystem models: A community perspective

Here, we present a community perspective on how to explore, exploit and evolve the diversity in aquatic ecosystem models. These models play an important role in understanding the functioning of aquatic ecosystems, filling in observation gaps and developing effective strategies for water quality management. In this spirit, numerous models have been developed since the 1970s. We set off to explore model diversity by making an inventory among 42 aquatic ecosystem modellers, by categorizing the resulting set of models and by analysing them for diversity. We then focus on how to exploit model diversity by comparing and combining different aspects of existing models. Finally, we discuss how model diversity came about in the past and could evolve in the future. Throughout our study, we use analogies from biodiversity research to analyse and interpret model diversity. We recommend to make models publicly available through open-source policies, to standardize documentation and technical implementation of models, and to compare models through ensemble modelling and interdisciplinary approaches. We end with our perspective on how the field of aquatic ecosystem modelling might develop in the next 5–10 years. To strive for clarity and to improve readability for non-modellers, we include a glossary
Targeting at-risk students using engagement and effort predictors in an introductory computer programming course

This paper presents a new approach to automatically detect- ing lower-performing or “at-risk” students on computer programming modules in an undergraduate University degree course. Using histori- cal data from previous student cohorts we built a predictive model using logged interactions between students and online resources, as well as stu- dents’ progress in programming laboratory work. Predictions were cal- culated each week during a 12-week semester. Course lecturers received student lists ranked by their probability of failing the next computer- based laboratory exam. At-risk students were targeted and offered assis- tance during laboratory sessions by the lecturer and laboratory tutors. When we group students into two cohorts depending on whether they failed or passed their first laboratory exam, the average margin of im- provement on the second laboratory exam between the higher and lower- performing students was four times higher when our predictions were run and subsequent laboratory support targeted at these students, compared to students from the year our model was trained on
A study on the effects of routing symbol design on process model comprehension

Process modeling grammars are used to create models of business processes. In this paper, we discuss how different routing symbol designs affect an individual's ability to comprehend process models. We conduct an experiment with 154 students to ascertain which visual design principles influence process model comprehension. Our findings suggest that design principles related to perceptual discriminability and pop out improve comprehension accuracy. Furthermore, semantic transparency and aesthetic design of symbols lower the perceived difficulty of comprehension. Our results inform important principles about notational design of process modeling grammars and the effective use of process modeling in practice
Developing, deploying and assessing usage of a movie archive system among students of film studies

This paper describes our work in developing a movie browser application for students of Film Studies at our University. The aim of our work is to address the issues that arise when applying conventional user-centered design techniques from the usability engineering field to build a usable application when the system incorporates novel multimedia tools that could be potentially useful to the end-users but have not yet been practiced or deployed. We developed a web-based system that incorporates features as identified from the students and those features from our novel video analysis tools, including scene detection and classification. We deployed the system, monitored usage and gathered quantitative and qualitative data. Our findings show those expected patterns and highlighted issues that need to be further investigated in a novel application development. A mismatch between the users’ wishes at the interviews and their actual usage was noted. In general, students found most of the provided features were beneficial for their studies
Dynamics of counterpropagating waves in parametrically driven systems: dispersion vs. advection

The dynamics of parametrically driven counterpropagating waves in a one-dimensional extended nearly conservative annular system are described by two coupled, damped, parametrically driven nonlinear Schrödinger (NLS) equations with opposite transport terms due to the group velocity, and small dispersion. The system is characterized by two length scales defined by a balance between (a) forcing and dispersion (the dispersive scale), and (b) forcing and advection at the group velocity (the transport scale). Both are large compared to the basic wavelength of the pattern. The dispersive scale plays an important role in the structure of solutions arising from secondary instabilities of frequency-locked spatially uniform standing waves (SW), and manifests itself both in traveling pulses or fronts and in extended spatio-temporal chaos, depending on the signs of the dispersion coefficient and nonlinearity.\ud
Author Keywords: Parametric resonance; Counterpropagating waves; Weak dispersion; Faraday wave
A Generic Bio-Economic Farm Model for Environmental and Economic Assessment of Agricultural Systems

Bio-economic farm models are tools to evaluate ex-post or to assess ex-ante the impact of policy and technology change on agriculture, economics and environment. Recently, various BEFMs have been developed, often for one purpose or location, but hardly any of these models are re-used later for other purposes or locations. The Farm System Simulator (FSSIM) provides a generic framework enabling the application of BEFMs under various situations and for different purposes (generating supply response functions and detailed regional or farm type assessments). FSSIM is set up as a component-based framework with components representing farmer objectives, risk, calibration, policies, current activities, alternative activities and different types of activities (e.g., annual and perennial cropping and livestock). The generic nature of FSSIM is evaluated using five criteria by examining its applications. FSSIM has been applied for different climate zones and soil types (criterion 1) and to a range of different farm types (criterion 2) with different specializations, intensities and sizes. In most applications FSSIM has been used to assess the effects of policy changes and in two applications to assess the impact of technological innovations (criterion 3). In the various applications, different data sources, level of detail (e.g., criterion 4) and model configurations have been used. FSSIM has been linked to an economic and several biophysical models (criterion 5). The model is available for applications to other conditions and research issues, and it is open to be further tested and to be extended with new components, indicators or linkages to other models
Elastic (stress-strain) halo associated to ion-induced nano-tracks in lithium niobate: role of crystal anisotropy

The elastic strain/stress fields (halo) around a compressed amorphous nano-track (core) caused by a single high-energy ion impact on LiNbO3 are calculated. A method is developed to approximately account for the effects of crystal anisotropy of LiNbO3 (symmetry 3m) on the stress fields for tracks oriented along the crystal axes (X, Y or Z). It only considers the zero-order (axial) harmonic contribution to the displacement field in the perpendicular plane and uses effective Poisson moduli for each particular orientation. The anisotropy is relatively small; however, it accounts for some differential features obtained for irradiations along the crystallographic axes X, Y and Z. In particular, the irradiation-induced disorder (including halo) and the associated surface swelling appear to be higher for irradiations along the X- or Y-axis in comparison with those along the Z-axis. Other irradiation effects can be explained by the model, e.g. fracture patterns or the morphology of pores after chemical etching of tracks. Moreover, it offers interesting predictions on the effect of irradiation on lattice parameter
Choosing the scope of trade secret law when secrets complement patents

We present a model where an incumbent firm has a proprietary product whose technology consists of at least two components, one of which is patented while the other is kept secret. At the patent expiration date, an entrant firm will enter the market on the same technological footing as the incumbent if it is successful in duplicating, at certain costs, the secret component of the incumbent’s technology. Otherwise, it will enter the market with a production cost disadvantage. We show that under some conditions a broad scope of trade secret law is socially beneficial despite the innovator is over-rewarded.
Thermal effect of plastic dissipation at the crack tip on the stress intensity factor under cyclic loading

The authors acknowledge Arts et Métiers ParisTech and Fondation Arts et Métiers for the financial support of Paul C. Paris’ stay at LAMEFIP in 2009. The encouragement of Prof. Ivan Iordanoff, Director of LAMEFIP, is acknowledged with thanks. The effective mathematical assistance of Dr. Hiroshi Tada is also acknowledged.Plastic dissipation at the crack tip under cyclic loading is responsible for the creation of an heterogeneous temperature field around the crack tip. A thermomechanical model is proposed in this paper for the theoretical problem of an infinite plate with a semi-infinite through crack under mode I cyclic loading both in plane stress or in plane strain condition.
It is assumed that the heat source is located in the reverse cyclic plastic zone. The proposed analytical solution of the thermo-mechanical problem shows that the crack tip is under compression due to thermal stresses coming from the heterogeneous stress field around the crack tip. The effect of this stress field on the stress intensity factor (its maximum and its range) is calculated analytically for the infinite plate and by finite element analysis.
The heat flux within the reverse cyclic plastic zone is the key parameter to quantify the
effect of dissipation at the crack tip on the stress intensity facto
Role of intragranular microstructure development in the macroscopic behavior of multiphase steels in the context of changing strain paths

Sheet metal forming processes are commonly associated with strain-path changes in the material. Macroscopic softening/hardening transient effects can appear due to the plastic anisotropy induced by these deformation stages. Such characteristic effects can mainly be ascribed to the intragranular microstructure development and its evolution. It subsequently becomes necessary to accurately describe the dislocation patterning during monotonic and sequential loading paths in order to obtain a relevant constitutive model. In the present work, three types of local dislocation densities are taken to represent the spatially heterogeneous distributions of dislocations inside the grain. The resulting large strain single crystal constitutive law, based on crystal plasticity, is incorporated into a self-consistent scale-transition scheme. With the help of a rate-independent regularization technique, this new extended multiscale model is able to calculate plastic slip activity for each grain, and it can also characterize the evolution of the dislocation microstructure. We show that our model successfully reproduces several mechanisms of intragranular substructure development that have been observed in TEM micrographs in the context of various loading conditions. Our approach is also capable of quantitatively predicting the macroscopic behavior of both single-phase and dual-phase polycrystalline steels in the context of changing strain paths.ArcelorMittal & CNR