We derive the collision term relevant for neutrino quantum kinetic equations in the early universe and compact astrophysical objects, displaying its full matrix structure in both flavor and spin degrees of freedom. We include in our analysis neutrino-neutrino processes, scattering and annihilation with electrons and positrons, and neutrino scattering off nucleons (the latter in the low-density limit). After presenting the general structure of the collision terms, we take two instructive limiting cases. The one-flavor limit highlights the structure in helicity space and allows for a straightforward interpretation of the off-diagonal entries in terms of the product of scattering amplitudes of the two helicity states. The isotropic limit is relevant for studies of the early universe: in this case the terms involving spin coherence vanish and the collision term can be expressed in terms of two-dimensional integrals, suitable for computational implementation.

Motivated by the recent construction of a translation-invariant renormalizable non-commutative model for a scalar field [1], we introduce models for non-commutative U (1) gauge fields along the same lines. More precisely, we include some extra terms into the action with the aim of getting rid of the UV/IR mixing.

We give an introduction to, and review of, the energy-momentum tensors in classical gauge field theories in Minkowski space, and to some extent also in curved space-time. For the canonical energy-momentum tensor of non-Abelian gauge fields and of matter fields coupled to such fields, we present a new and simple improvement procedure based on gauge invariance for constructing a gauge invariant, symmetric energy-momentum tensor. The relationship with the Einstein-Hilbert tensor following from the coupling to a gravitational field is also discussed. Plan of the paper:In the present note we focus, for classical YM (Yang-Mills) theories in ndimensional Minkowski space, on the EMT (energy-momentum tensor, also referred to as stressenergy tensor or stress tensor for short): the components T µν of the EMT can be interpreted as follows, e.g. see reference [12]. T 00 represents the energy density, T 0i the i-momentum density (or energy flux density) and T ij the i-momentum flux density in the j-direction. Regarding the field theoretical system as a collection of particles, we can also interpret T ii ≡ p as the pressure and (T ij ) with i = j as the shear stress. In particular, we will study here the so-called canonical EMT whose components T µν can represent the conserved current densities which are associated (by virtue of Noether's first theorem) to the invariance of the action under spacetime translations. The corresponding conserved charges P ν ≡ R n−1 d n−1 x T 0ν can define the total energy and momentum of the physical system.As is well known (for instance for Maxwell's theory), the tensor T µν can is neither symmetric nor gauge invariant in general and thereby needs to be "improved". This is traditionally realized by the "symmetrization procedure of Belinfante" [13,14] which relies on the spin angular momentum density, but this method does not work straightforwardly in the case where matter fields are minimally coupled to a gauge field [15]. After a short introduction to the subject and problematics in subsection 2.1, we will show in subsection 2.2 that the improvement can be realized in a simple manner for pure gauge fields or for interacting gauge and matter fields by taking into account the local gauge invariance 1 . A conceptually quite different approach consists of coupling the gauge and matter fields to gravity and deducing the so-called Einstein-Hilbert EMT in Minkowski space from the metric EMT on curved space. This approach is outlined for YM theories in section 3 and it is readily shown that the different results in Minkowski space coincide with each other. Concerning the latter point we should mention that more general and abstract approaches have been considered in the literature (we refer in particular to the systematic study [17] based on the earlier work [18]), but we hope that the elementary discussion of the different aspects presented here is useful both as a short introduction to, and as an overview of, the subject. While our paper is devoted to the classical theory, we conclude with some remarks...

The mobility of dislocations is an important factor in understanding material strength. Dislocations experience a drag due to their interaction with the crystal structure, the dominating contribution at high stress and temperature being the scattering off phonons due to phonon wind. Yet, the velocity dependence of this effect has eluded a good theoretical understanding. In a previous paper, dislocation drag from phonon wind as a function of velocity was computed from first principles in the isotropic limit, in part for simplicity, but also arguing that macroscopically, a polycrystalline metal looks isotropic. However, since the single crystal grains are typically a few microns up to a millimeter in size, dislocations travel in single crystals and cross boundaries, but never actually see an isotropic material. In this work we therefore highlight the effect of crystal anisotropy on dislocation drag by accounting for the crystal and slip plane geometries. In particular, we keep the phonon spectrum isotropic for simplicity, but dislocations are modeled according to the crystal symmetry (bcc, fcc, hcp, etc.). We then compare to the earlier purely isotropic results, as well as to experimental data and MD simulations where they are available.

BackgroundFabry disease (FD) is an X-linked multisystemic disorder with a heterogeneous phenotype. Especially atypical or late-onset type 2 phenotypes present a therapeutical dilemma.MethodsTo determine the clinical impact of the alpha-Galactosidase A (GLA) p.A143T/ c.427G > A variation, we retrospectively analyzed 25 p.A143T patients in comparison to 58 FD patients with other missense mutations.Resultsp.A143T patients suffering from stroke/ transient ischemic attacks had slightly decreased residual GLA activities, and/or increased lyso-Gb3 levels, suspecting FD. However, most male p.A143T patients presented with significant residual GLA activity (~50 % of reference), which was associated with normal lyso-Gb3 levels. Additionally, p.A143T patients showed less severe FD-typical symptoms and absent FD-typical renal and cardiac involvement in comparison to FD patients with other missense mutations. Two tested female p.A143T patients with stroke/TIA did not show skewed X chromosome inactivation. No accumulation of neurologic events in family members of p.A143T patients with stroke/transient ischemic attacks was observed.ConclusionsWe conclude that GLA p.A143T seems to be most likely a neutral variant or a possible modifier instead of a disease-causing mutation. Therefore, we suggest that p.A143T patients with stroke/transient ischemic attacks of unknown etiology should be further evaluated, since the diagnosis of FD is not probable and subsequent ERT or chaperone treatment should not be an unreflected option.Electronic supplementary materialThe online version of this article (doi:10.1186/s13023-016-0441-z) contains supplementary material, which is available to authorized users.

Because of the shortage of agalsidase-b supply between 2009 and 2012, patients with Fabry disease either were treated with reduced doses or were switched to agalsidase-a. In this observational study, we assessed end organ damage and clinical symptoms with special focus on renal outcome after 2 years of dose-reduction and/or switch to agalsidase-a.Atotalof89adultpatientswithFabrydiseasewhohadreceivedagalsidase-b (1.0mg/kgbodywt)for.1 yearwerenonrandomlyassignedtocontinuethistreatmentregimen(regular-dosegroup,n=24),toreceiveareduced dose of 0.3-0.5 mg/kg and a subsequent switch to 0.2 mg/kg agalsidase-a (dose-reduction-switch group, n=28), or to directly switch to 0.2 mg/kg agalsidase-a (switch group, n=37) and were followed-up for 2 years. We assessed clinical events (death, myocardial infarction, severe arrhythmia, stroke, progression to ESRD), changes in cardiac and renal function, Fabry-related symptoms (pain, hypohidrosis, diarrhea), and disease severity scores. Determination of renal functionbycreatinineandcystatinC-basedeGFRrevealeddecreasingeGFRsinthedose-reduction-switchgroupand the switch group. The Mainz Severity Score Index increased significantly in these two groups (P=0.02 and P,0.001, respectively), and higher frequencies of gastrointestinal pain occurred during follow-up. In conclusion, after 2 years of observation,allgroupsshowedastableclinicaldiseasecoursewithrespecttoseriousclinicalevents.However,patients under agalsidase-b dose-reduction and switch or a direct switch to agalsidase-a showed a decline of renal function independent of the eGFR formula used.

At extreme strain rates, where fast moving dislocations govern plastic deformation, anharmonic phonon scattering imparts a drag force on the dislocations. In this paper, we present calculations of the dislocation drag coefficients of aluminum and copper as functions of temperature and density. We discuss the sensitivity of the drag coefficients to changes in the third-order elastic constants with temperature and density.

When considering quantum field theories on non-commutative spaces one inevitably encounters the infamous UV/IR mixing problem. So far, only very few renormalizable models exist and all of them describe non-commutative scalar field theories on fourdimensional Euclidean Groenewold-Moyal deformed space, also known as 'θ-deformed space' R 4 θ . In this work we discuss some major obstacles of constructing a renormalizable non-commutative gauge field model and sketch some possible ways out.