Tortuous ways to the extraction of neutron observables from inclusive lepton scattering

We analyze new JLAB data for inclusive electron scattering on various targets. Computed and measured total inclusive cross sections in the range $0.3\lesssim x\lesssim 0.95$ show on a logarithmic scale reasonable agreement for all targets. However, closer inspection of the Quasi-Elastic components bares serious discrepancies. EMC ratios which may contain less systematic errors fare the same. The above observations for the new data do not enable the extraction of the magnetic form factor (FF) $G_M^n$ and the Structure Function (SFs) $F_2^n$ of the neutron, although the application of exactly the same analysis to older data had been successful. We add to the above analysis older CLAS collaboration on $F_2^D$. Removing some scattered points, it appears possible to obtain the above mentioned neutron information. We compare our results with others from alternative sources. Particular attention is paid to the A=3 iso-doublet. Present data exist only for $^3$He, but the available input and charge symmetry also enable computations for $^3$H. Their average is the computed iso-scalar part and is compared with the empirical modification of $^3$He towards a fictitious A=3 iso-singlet.Comment: 27 pages, 30 figure

Algebraically decaying modes and wave packet pseudo-modes in swept Hiemenz flow

The modal structure of the swept Hiemenz flow, a model for the flow near the attachment line of a swept wing, consists of eigenfunctions which exhibit (super-)exponential or algebraic decay as the wall-normal coordinate tends to infinity. The subset of algebraically decaying modes corresponds to parts of the spectrum which are characterized by a significant sensitivity to numerical discretization. Numerical evidence further suggests that a continuous spectrum covering a two-dimensional range of the complex plane exists. We investigate the family of uniform swept Hiemenz modes using eigenvalue computations, numerical simulations and the concept of wave packet pseudo-modes. Three distinct branches of the family of algebraically decaying eigenmodes are identified. They can be superimposed to produce wavefronts propagating towards or away from the boundary layer and standing or travelling wave packets in the free stream. Their role in the exchange of information between the free stream and the attachment-line boundary layer for the swept Hiemenz flow is discussed. The concept of wave packet pseudo-modes has been critical in the analysis of this problem and is expected to lead to further insights into other shear flows in semi- or bi-infinite domain

Increasing market efficiency: Evolution of cross-correlations of stock returns

We analyse the temporal changes in the cross correlations of returns on the New York Stock Exchange. We show that lead-lag relationships between daily returns of stocks vanished in less than twenty years. We have found that even for high frequency data the asymmetry of time dependent cross-correlation functions has a decreasing tendency, the position of their peaks are shifted towards the origin while these peaks become sharper and higher, resulting in a diminution of the Epps effect. All these findings indicate that the market becomes increasingly efficient.Comment: 12 pages, 8 figures, accepted to Physica

Natural conditions in agriculture and the regional distribution of EU producer support

The redistributive implications of the Common Agricultural Policy (CAP) of the European Union (EU) have regained a strong interest in recent years since economic and social cohe-sion has become a major goal of European policy. The empirical evidence is surprisingly di-verse and ranges from a clearly positive to a clearly negative regional redistributive impact of the CAP. Therefore, the objectives of this paper are threefold. First, the interregional alloca-tion of EU producer support under the CAP is measured at the NUTS III-level in the period 1986-2002 for 26 regions of the German Bundesland Hesse. Second, the role of the measure-ment concept for the magnitude and distribution of the regional transfers is elaborated. Third, the interregional allocation of EU producer support is explained by natural conditions and farm structure variables within a quantitative analysis. A major result is that the interregional allocation of producer support is unequal, depends on the measure of protection used and is affected by a number of variables characterizing farm structure and natural conditions

A roadmap to integrate astrocytes into Systems Neuroscience.

Systems neuroscience is still mainly a neuronal field, despite the plethora of evidence supporting the fact that astrocytes modulate local neural circuits, networks, and complex behaviors. In this article, we sought to identify which types of studies are necessary to establish whether astrocytes, beyond their well-documented homeostatic and metabolic functions, perform computations implementing mathematical algorithms that sub-serve coding and higher-brain functions. First, we reviewed Systems-like studies that include astrocytes in order to identify computational operations that these cells may perform, using Ca2+ transients as their encoding language. The analysis suggests that astrocytes may carry out canonical computations in a time scale of subseconds to seconds in sensory processing, neuromodulation, brain state, memory formation, fear, and complex homeostatic reflexes. Next, we propose a list of actions to gain insight into the outstanding question of which variables are encoded by such computations. The application of statistical analyses based on machine learning, such as dimensionality reduction and decoding in the context of complex behaviors, combined with connectomics of astrocyte-neuronal circuits, is, in our view, fundamental undertakings. We also discuss technical and analytical approaches to study neuronal and astrocytic populations simultaneously, and the inclusion of astrocytes in advanced modeling of neural circuits, as well as in theories currently under exploration such as predictive coding and energy-efficient coding. Clarifying the relationship between astrocytic Ca2+ and brain coding may represent a leap forward toward novel approaches in the study of astrocytes in health and disease