Restoring Bankruptcy’s Fresh Start

The discharge injunction, which allows former debtors to be free from any efforts to collect former debt, is a primary feature of bankruptcy law in the United States. When creditors have systemically violated debtors’ discharge injunctions, some debtors have attempted to challenge those creditors through a class action lawsuit in bankruptcy court. However, the pervasiveness of class-waiving arbitration clauses likely prevents those debtors from disputing discharge injunction violations outside of binding, individual arbitration. This Note first discusses areas of disagreement regarding how former debtors may enforce their discharge injunctions. Then, it examines the types of disputes that allow debtors to collectivize in bankruptcy court. Without seeking to resolve either disagreement, this Note assumes debtors may collectivize in this context and employs an “inherent conflict” test that looks to whether disputes over discharge injunction violations are arbitrable. Because the “inherent conflict” test likely leads to the conclusion that courts must enforce class-waiving arbitration clauses, this Note argues that Congress should amend the Bankruptcy Code not only to provide debtors an express right of action under § 524 and the ability to collectivize, but also to prohibit the arbitration of these claims. Doing so will give full effect to the discharge injunction and fulfill the promise to debtors that they can truly begin anew after bankruptcy

Heterogeneous connections induce oscillations in large scale networks

Realistic large-scale networks display an heterogeneous distribution of connectivity weights, that might also randomly vary in time. We show that depending on the level of heterogeneity in the connectivity coefficients, different qualitative macroscopic and microscopic regimes emerge. We evidence in particular generic transitions from stationary to perfectly periodic phase-locked regimes as the disorder parameter is increased, both in a simple model treated analytically and in a biologically relevant network made of excitable cells

Noise-induced behaviors in neural mean field dynamics

The collective behavior of cortical neurons is strongly affected by the presence of noise at the level of individual cells. In order to study these phenomena in large-scale assemblies of neurons, we consider networks of firing-rate neurons with linear intrinsic dynamics and nonlinear coupling, belonging to a few types of cell populations and receiving noisy currents. Asymptotic equations as the number of neurons tends to infinity (mean field equations) are rigorously derived based on a probabilistic approach. These equations are implicit on the probability distribution of the solutions which generally makes their direct analysis difficult. However, in our case, the solutions are Gaussian, and their moments satisfy a closed system of nonlinear ordinary differential equations (ODEs), which are much easier to study than the original stochastic network equations, and the statistics of the empirical process uniformly converge towards the solutions of these ODEs. Based on this description, we analytically and numerically study the influence of noise on the collective behaviors, and compare these asymptotic regimes to simulations of the network. We observe that the mean field equations provide an accurate description of the solutions of the network equations for network sizes as small as a few hundreds of neurons. In particular, we observe that the level of noise in the system qualitatively modifies its collective behavior, producing for instance synchronized oscillations of the whole network, desynchronization of oscillating regimes, and stabilization or destabilization of stationary solutions. These results shed a new light on the role of noise in shaping collective dynamics of neurons, and gives us clues for understanding similar phenomena observed in biological networks

Continuity of robustness measures in quantum resource theories

Robustness measures are increasingly prominent resource quantifiers that have been introduced for quantum resource theories such as entanglement and coherence. Despite the generality of these measures, their usefulness is hindered by the fact that some of their mathematical properties remain unclear, especially when the set of resource-free states is non-convex. In this paper, we investigate continuity properties of different robustness functions. We show that their continuity depends on the shape of the set of free states. In particular, we demonstrate that in many cases, star-convexity is sufficient for Lipschitz-continuity of the robustness, and we provide specific examples of sets leading to non-continuous measures. Finally, we illustrate the applicability of our results by defining a robustness of teleportability and of quantum discord.Comment: 13 pages, 3 figure

Numerical Integrators for Physical Applications

In this thesis, we report on our work in two very fundamental fields of physics which still have not been merged in a satisfactory way by a combining physical theory. One area is the field of very small particles, most accurately described by quantum mechanics. Here, we are interested in the phenomenon of superconductivity. The other area is that of the very heavy objects of our universe. Their most fundamental description is based on the theory of general relativity. Our particular interest lies in binary systems of compact objects rotating around each other, constantly radiating gravitational waves in the process. Although quantum mechanics and general relativity are worlds apart from a physical point of view, they inhibit some analogies when seen from our numerical perspective. For our aim is the same in both fields: We want to provide numerical tools for the simulations of interesting physical processes. Regarding binary systems we want to compare two descriptions of their motion in space. The first is given by the Mathisson--Papapetrou equations. In order to study the evolution as given by these equations, we develop an efficient integration scheme based on Gauss Runge--Kutta methods. An intriguing challenge is given by the fact that part of the equations of motion have only be given implicitly. All obstacles notwithstanding, we present an efficient integrator which preserves the constants of motion even over long times. The second description of a binary's motion is given by a Hamiltonian approximation of the Mathisson--Papapetrou equations. We want to study whether this prescription yields physically valid results. To this aim, we first come up with an efficient numerical evolution scheme, again recurring to Gauss Runge-Kutta integrators. Our scheme conserves the Hamiltonian structure, thus yielding reliable results for long time spans. Then, we test the Hamiltonian approach in different aspects. When studying the behavior of important constants of motion, we have found out that the Hamiltonian in its originally published form must be based on unphysical assumptions. This triggered new theoretical studies by our collaborators from physics with the aim of finding better suited alternatives. Their new results and suggestions are tested with the help of our algorithms. The --now physically reasonable-- Hamiltonian descriptions are well-suited to investigate the binary systems for chaos with the help of surface sections. Hence, we take use of the collocation property of the Gauss Runge--Kutta schemes to present an accurate and convenient algorithm for the calculation of such sections. In the realm of superconductivity, we consider the time-dependent BCS equations. These are quite involved partial differential equations describing the evolution of the Cooper pair density within a superconducting material or a superfluid. A very hot topic in the theoretical physics community concerns the question as to whether there exists, close to the critical temperature, a more convenient equation for a reliable approximation on a macroscopic scale. We take on this question from a numerical point of view. For this, we compare the evolution of a system with contact interaction given by the BCS equations to the one obtained via a linearized approximation by means of a thorough numerical study. We concentrate on a translation invariant system and develop two new numerical solvers based on so-called splitting methods. Splitting the coupled equations into more convenient subproblems and aptly combining the partial results, we come up with efficient and accurate schemes whose CPU times depend only linearly on the number of basis functions of the space discretization. With the help of the Fast Fourier Transform (FFT) algorithm, we can even extend our integrators to general potentials in a very natural way. In this case, too, the CPU effort grows only mildly as a function of the number of basis functions. In the physically relevant case of a fermionic system interacting via a contact interaction, we employ our newly developed schemes to conduct numerous simulations for temperatures closer and closer to the critical one. From these simulations, we conclude that the linearization deviates far from the original equations. More precisely, the linear approximation leads to an exponential decay of the Cooper pair density whereas the full equations yield oscillations about a finite value. Consequently, the diffusion which is inherent to all hitherto existing macroscopic theories can only be an unphysical artifact. With this, we add an important fact to the still ongoing discussion in the physics community. In short, we successfully developed convenient tools for the simulation of important physical phenomena in two fundamental fields of physics. This allowed our collaborators to gain valuable insights into the behavior of their equations of interest, thus contributing to the advance of fundamental science

A metaproteomic approach to study human-microbial ecosystems at the mucosal luminal interface

Aberrant interactions between the host and the intestinal bacteria are thought to contribute to the pathogenesis of many digestive diseases. However, studying the complex ecosystem at the human mucosal-luminal interface (MLI) is challenging and requires an integrative systems biology approach. Therefore, we developed a novel method integrating lavage sampling of the human mucosal surface, high-throughput proteomics, and a unique suite of bioinformatic and statistical analyses. Shotgun proteomic analysis of secreted proteins recovered from the MLI confirmed the presence of both human and bacterial components. To profile the MLI metaproteome, we collected 205 mucosal lavage samples from 38 healthy subjects, and subjected them to high-throughput proteomics. The spectral data were subjected to a rigorous data processing pipeline to optimize suitability for quantitation and analysis, and then were evaluated using a set of biostatistical tools. Compared to the mucosal transcriptome, the MLI metaproteome was enriched for extracellular proteins involved in response to stimulus and immune system processes. Analysis of the metaproteome revealed significant individual-related as well as anatomic region-related (biogeographic) features. Quantitative shotgun proteomics established the identity and confirmed the biogeographic association of 49 proteins (including 3 functional protein networks) demarcating the proximal and distal colon. This robust and integrated proteomic approach is thus effective for identifying functional features of the human mucosal ecosystem, and a fresh understanding of the basic biology and disease processes at the MLI. © 2011 Li et al

The self-assembly and evolution of homomeric protein complexes

We introduce a simple "patchy particle" model to study the thermodynamics and dynamics of self-assembly of homomeric protein complexes. Our calculations allow us to rationalize recent results for dihedral complexes. Namely, why evolution of such complexes naturally takes the system into a region of interaction space where (i) the evolutionarily newer interactions are weaker, (ii) subcomplexes involving the stronger interactions are observed to be thermodynamically stable on destabilization of the protein-protein interactions and (iii) the self-assembly dynamics are hierarchical with these same subcomplexes acting as kinetic intermediates.Comment: 4 pages, 4 figure

Survivance de la Riziculture Pluviale dans le Departement De Bouake : Des Anomalies Pluviometriques a L’adaptation Paysanne

Les changements climatiques constituent une  menace majeure pour la production agricole. Ses effets en  riziculture pluviale se ressentent  par le changement de son calendrier cultural. L’objectif de cette contribution est d’analyser l’évolution de la pluviométrie de même que les pratiques endogènes. Pour cette étude, il fut utilisé des données climatiques mensuelles (pluviométrie, évapotranspiration potentielle) de 1980 à 2020. A partir de la méthode de Franquin, il a déterminé les périodes pré-humide, humide et post-humide et le calendrier cultural du riz pluvial pour le département de Bouaké. Les résultats obtenus révèlent que pendant la phase pré-humide (Mars à juin), la durée de cette phase est de 14 jours en moyenne par an entre le semis et le tallage. Quant à la phase humide (juillet à octobre), elle dure en moyenne 45 jours par an. Tandis que la phase post-humide (octobre à décembre) dure 65 jours par an en moyenne. Dans cette période, on peut cultiver le riz pluvial dont le cycle est inférieur ou égal à 120 jours. La saison culturale débute en mars (A2) pour prendre fin en décembre (C2).  Mais selon les riziculteurs enquêtés la saison culturale débute quelques semaines avant juillet (B1 ou début de la saison cultural) et se terminer en décembre (C2). À ce titre, la période préparatoire du sol se situe entre un ou deux mois avant juillet. Le repiquage est exigé en juillet (B1) afin d’obtenir théoriquement un résultat satisfaisant de la production. Ainsi, comme stratégies endogènes, les riziculteurs du département de Bouaké adoptent plusieurs stratégies qui se résument à l’adaptation de nouvelles méthodes de la riziculture à savoir changement du système cultural du riz. Concernant les techniques culturales, les riziculteurs modifient leur date de semis.  Avant c’était dans le mois de mai maintenant elle se fait en juin en vue d’une bonne récolte. Pour le riz pluvial, les riziculteurs commencent le repiquage à partir juillet à août pour s’adapté aux modifications du climat car ce type de riziculture se fait durant la saison pluvieuse.   Climate change poses a major threat to agricultural production. Its effects in rainfed rice cultivation are felt by the change in its cropping calendar. The objective of this contribution is to analyze the evolution of rainfall as well as endogenous practices. For this study, monthly climatic data (rainfall, potential evapotranspiration) from 1980 to 2020 were used and Franquin's method was applied to determine the periods as well as the rainfed rice cropping calendar for the department of Bouaké. The results obtained reveal that the rainy season is divided into three phases (pre-wet, wet and post-wet period). To this end, during the pre-wet phase (March to June), the duration between sowing and tillering is 14 days on average following field surveys. As for the wet phase (July to October), it lasts an average of 45 days per year. While the post-humid phase (October to December) lasts 65 days per year on average. During this wet period, rainfed rice can be grown, the cycle of which is less than or equal to 120 days. With Franquin's method, the growing season begins in March (A2) and ends in December (C2). But according to the rice farmers surveyed, the growing season begins a few weeks before July (B1 or start of the growing season) and ends in December (C2). As such, the preparatory period for the soil is between January and mid-June. Transplanting is required in July (B1) in order to theoretically obtain a satisfactory production result. Thus, as endogenous strategies, the rice farmers of the department of Bouaké adopt several strategies which boil down to the adaptation of new methods of rice cultivation, namely change of the rice cultivation system. Regarding cultivation techniques, rice farmers change their sowing date. For upland rice, transplanting is done from July to August to adapt to climate changes