An Outline of a Progressive Resolution to the Euro-area Sovereign Debt Overhang: How a Five year Suspension of the Debt Burden Could Overthrow Austerity

The present study puts forward a plan for solving the sovereign debt crisis in the euro area (EA) in line with the interests of the working classes and the social majority. Our main strategy is for the European Central Bank (ECB) to acquire a significant part of the outstanding sovereign debt (at market prices) of the countries in the EA and convert it to zero-coupon bonds. No transfers will take place between individual states; taxpayers in any EA country will not be involved in the debt restructuring of any foreign eurozone country. Debt will not be forgiven: individual states will agree to buy it back from the ECB in the future when the ratio of sovereign debt to GDP has fallen to 20 percent. The sterilization costs for the ECB are manageable. This model of an unconventional monetary intervention would give progressive governments in the EA the necessary basis for developing social and welfare policies to the benefit of the working classes. It would reverse present-day policy priorities and replace the neoliberal agenda with a program of social and economic reconstruction, with the elites paying for the crisis. The perspective taken here favors social justice and coherence, having as its priority the social needs and the interests of the working majority

Dynamic Modeling of Bucket-Soil Interactions Using Koopman-DFL Lifting Linearization for Model Predictive Contouring Control of Autonomous Excavators

A lifting-linearization method based on the Koopman operator and Dual Faceted Linearization is applied to the control of a robotic excavator. In excavation, a bucket interacts with the surrounding soil in a highly nonlinear and complex manner. Here, we propose to represent the nonlinear bucket-soil dynamics with a set of linear state equations in a higher-dimensional space. The space of independent state variables is augmented by adding variables associated with nonlinear elements involved in the bucket-soil dynamics. These include nonlinear resistive forces and moment acting on the bucket from the soil, and the effective inertia of the bucket that varies as the soil is captured into the bucket. Variables associated with these nonlinear resistive and inertia elements are treated as additional state variables, and their time evolution is represented as another set of linear differential equations. The lifted linear dynamic model is then applied to Model Predictive Contouring Control, where a cost functional is minimized as a convex optimization problem thanks to the linear dynamics in the lifted space. The lifted linear model is tuned based on a data-driven method by using a soil dynamics simulator. Simulation experiments verify the effectiveness of the proposed lifting linearization compared to its counterpart

On the effect of receiver impairments on incoherent QAM systems

Incoherent QAM is a differentially detected, multilevel modulation format that can improve spectral efficiency in optical communication systems. The effect of three receiver impairments on the performance of an incoherent QAM system is assessed in this paper for the first time. Specifically, the impairments studied are an unbalanced Mach-Zehnder Interferometer (MZI,), the phase detuning of the MZI and the amplitude imbalance of the Balanced Photodetectors (BPD). Extensive simulations were carried out and results indicate that incoherent QAM is quite robust in respect to the aforementioned impairments, with the phase detuning being the most critical parameter leading to peiformance degradatio

Multi-level modulation formats for optical access networks

There is growing demand for higher bit rates at the access domain. The most promising and future-proof technology for providing end users with high bandwidth is Passive Optical Networks (PON). In order to provide these higher bit rates, the use of multi-level modulation has been proposed. By moving to multi-level signals, low speed electronics can be used, with some added complexity to the optical part. This paper investigates the performance of incoherent multi-level modulation formats (in particular QAM and DQPSK) in bidirectional PONs. The simulation results indicate that incoherent QAM is a strong candidate for future PONs

Automatic, fast and robust characterization of noise distributions for diffusion MRI

Knowledge of the noise distribution in magnitude diffusion MRI images is the centerpiece to quantify uncertainties arising from the acquisition process. The use of parallel imaging methods, the number of receiver coils and imaging filters applied by the scanner, amongst other factors, dictate the resulting signal distribution. Accurate estimation beyond textbook Rician or noncentral chi distributions often requires information about the acquisition process (e.g. coils sensitivity maps or reconstruction coefficients), which is not usually available. We introduce a new method where a change of variable naturally gives rise to a particular form of the gamma distribution for background signals. The first moments and maximum likelihood estimators of this gamma distribution explicitly depend on the number of coils, making it possible to estimate all unknown parameters using only the magnitude data. A rejection step is used to make the method automatic and robust to artifacts. Experiments on synthetic datasets show that the proposed method can reliably estimate both the degrees of freedom and the standard deviation. The worst case errors range from below 2% (spatially uniform noise) to approximately 10% (spatially variable noise). Repeated acquisitions of in vivo datasets show that the estimated parameters are stable and have lower variances than compared methods.Comment: v2: added publisher DOI statement, fixed text typo in appendix A

An operator expansion for the elastic limit

A leading twist expansion in terms of bi-local operators is proposed for the structure functions of deeply inelastic scattering near the elastic limit $x \to 1$, which is also applicable to a range of other processes. Operators of increasing dimensions contribute to logarithmically enhanced terms which are supressed by corresponding powers of $1-x$. For the longitudinal structure function, in moment ($N$) space, all the logarithmic contributions of order $\ln^k N/N$ are shown to be resummable in terms of the anomalous dimension of the leading operator in the expansion.Comment: 9 pages, 1 figure, uses REVTEX 3.1 and axodra

Tau mislocation in glucocorticoid-triggered hippocampal pathology

The exposure to high glucocorticoids (GC) triggers neuronal atrophy and cognitive deficits, but the exact cellular mechanisms underlying the GC-associated dendritic remodeling and spine loss are still poorly understood. Previous studies have implicated sustained GC elevations in neurodegenerative mechanisms through GC-evoked hyperphosphorylation of the cytoskeletal protein Tau while Tau mislocation has recently been proposed as relevant in Alzheimer's disease (AD) pathology. In light of the dual cytoplasmic and synaptic role of Tau, this study monitored the impact of prolonged GC treatment on Tau intracellular localization and its phosphorylation status in different cellular compartments. We demonstrate, both by biochemical and ultrastructural analysis, that GC administration led to cytosolic and dendritic Tau accumulation in rat hippocampus, and triggered Tau hyperphosphorylation in epitopes related to its malfunction (Ser396/404) and cytoskeletal pathology (e.g., Thr231 and Ser262). In addition, we show, for the first time, that chronic GC administration also increased Tau levels in synaptic compartment; however, at the synapse, there was an increase in phosphorylation of Ser396/404, but a decrease of Thr231. These GC-triggered Tau changes were paralleled by reduced levels of synaptic scaffolding proteins such as PSD-95 and Shank proteins as well as reduced dendritic branching and spine loss. These in vivo findings add to our limited knowledge about the underlying mechanisms of GC-evoked synaptic atrophy and neuronal disconnection implicating Tau missorting in mechanism(s) of synaptic damage, beyond AD pathology.We would like to thank Rui Fernandes for TEM technical support. IS was supported by the Portuguese Foundation for Science and Technology (FCT).This work was funded by the Portuguese Foundation for Science and Technology (FCT) (grant NMC-113934 to IS and grant SFRH/BPD/80118/2011 to JC), Canon Foundation and project DoIT - Desenvolvimento e Operacionalização da Investigação de Translação (N° do projeto 13853), funded by Fundo Europeu de Desenvolvimento Regional (FEDER) through the Programa Operacional Fatores de Competitividade (POFC).info:eu-repo/semantics/publishedVersio

Wide-angle elastic scattering and color randomization

Baryon-baryon elastic scattering is considered in the independent scattering (Landshoff) mechanism. It is suggested that for scattering at moderate energies, direct and interchange quark channels contribute with equal color coefficients because the quark color is randomized by soft gluon exchange during the hadronization stage. With this assumption, it is shown that the ratio of cross sections $R_{\overline{p} p/ p p}$ at CM angle $\theta = 90^0$ decreases from a high energy value of R_{\pbar p / pp} \approx 1/2.7, down to R_{\pbar p / pp} \approx 1/28, compatible with experimental data at moderate energies. This sizable fall in the ratio seems to be characteristic of the Landshoff mechanism, in which changes at the quark level have a strong effect precisely because the hadronic process occurs via multiple quark scatterings. The effect of color randomization on the angular distribution of proton-proton elastic scattering and the cross section ratio $R_{np/pp}$ is also discussed.Comment: 18 pages, latex2e, 4 uuencoded figures, include