Non-unitarity of the leptonic mixing matrix in the TeV-scale type-I seesaw model

The non-unitarity effects in leptonic flavor mixing are regarded as one of the generic features of the type-I seesaw model. Therefore, we explore these effects in the TeV-scale type-I seesaw model, and show that there exist non-trivial correlations among the non-unitarity parameters, stemming from the typical flavor structure of the low-scale seesaw model. In general, it follows from analytical discussions and numerical results that all the six non-unitarity parameters are related to three model parameters, while the widely studied parameters η_eτ${\eta }_{e\tau }$ and η_μτ${\eta }_{\mu \tau }$ cannot be phenomenologically significant simultaneously.     

An adeno-associated viral vector transduces the rat hypothalamus and amygdala more efficient than a lentiviral vector

Background  

This study compared the transduction efficiencies of an adeno-associated viral (AAV) vector, which was pseudotyped with an AAV1 capsid and encoded the green fluorescent protein (GFP), with a lentiviral (LV) vector, which was pseudotyped with a VSV-G envelop and encoded the discosoma red fluorescent protein (dsRed), to investigate which viral vector transduced the lateral hypothalamus or the amygdala more efficiently. The LV-dsRed and AAV1-GFP vector were mixed and injected into the lateral hypothalamus or into the amygdala of adult rats. The titers that were injected were 1 × 10⁸ or 1 × 10⁹ genomic copies of AAV1-GFP and 1 × 10⁵ transducing units of LV-dsRed.     

Backlund transformations and exact solutions for a nonlinear elliptic equation modelling isothermal magnetostatic atmosphere

The equations of magnetostatic equilibria for a plasma in agravitational field are investigated analytically. For equilibriawith an ignorable spatial coordinate, the equations reduce toa single nonlinear elliptic equation for the magnetic potentialu known as the Grad-Shafranov equation. By specifying the arbitraryfunctions in this equation, a Liouville equation is obtained.Bäcklund transformations are described and applied to obtainexact solutions for the Liouville equation modelling an isothermalmagnetostatic atmosphere, in which the current density J isproportional to the exponential of the magnetic potential andmoveover falls off exponentially with distance vertical to thebase with an e-folding distance equal to the gravitational scaleheight.     

Semiconductor nanostructures enabled by aerosol technology

Aerosol technology provides efficient methods for producing nanoparticles with well-controlled composition and size distribution. This review provides an overview of methods and results obtained by using aerosol technology for producing nanostruetures for a variety of applications in semiconductor physics and device technology. Examples are given from： production of metal and metal alloy particles： semiconductor nanoparticles; semiconductor nanowires, grown both in the aerosol phase and on substrates; physics studies based on individual aerosol-generated devices; and large area deviees based on aerosol particles.     

Non-standard neutrino interactions in the Zee–Babu model

We investigate non-standard neutrino interactions (NSIs) in the Zee–Babu model. The size of NSIs predicted by this model is obtained from a full scan over the parameter space, taking into account constraints from low-energy experiments such as searches for lepton flavor violation (LFV) and the requirement to obtain a viable neutrino mass matrix. The dependence on the scale of new physics as well as on the type of the neutrino mass hierarchy is discussed. We find that NSIs at the source of a future neutrino factory may be at an observable level in the ν_e→ν_τ and/or ν_μ→ν_τ channels. In particular, if the doubly charged scalar of the model has a mass in reach of the LHC and if the neutrino mass hierarchy is inverted, a highly predictive scenario is obtained with observable signals at the LHC, in upcoming neutrino oscillation experiments, in LFV processes, and for NSIs at a neutrino factory.     

Metallic stripe in two dimensions: stability and spin-charge separation

The problems of charge stripe formation, spin-charge separation, and stability of the antiphase domain wall (ADW) associated with a stripe are addressed using an analytical approach to the t- J(z) model. We show that a metallic stripe together with its ADW is the ground state of the problem in the low doping regime. The stripe is described as a system of spinons and magnetically confined holons strongly coupled to the two dimensional spin environment with holon-spin-polaron elementary excitations filling a one-dimensional band.     

Microchip electroseparation of proteins using lipid-based nanoparticles

Porous liquid crystalline lipid-based nanoparticles are shown here to enable protein analysis in microchip electroseparation by reducing sample adsorption. Additionally, higher stability and reproducibility of the separations were observed. The method was tested by separating green fluorescent protein (GFP) in hot embossed cyclic olefin polymer microchips with integrated fiber grooves for LIF detection. The sample adsorption was indirectly quantified by measuring the height, width and asymmetry of the separation peaks for various concentrations of nanoparticles in the sample and background electrolyte. Without nanoparticles, electropherograms displayed typical signs of extensive adsorption to the channel walls, with low, broad tailing peaks. Higher, narrower more symmetric peaks were generated when 0.5-10% nanoparticles were added, showing a dramatic reduction of sample adsorption. The current through the separation channel decreased with nanoparticle concentration, reducing to half its value when the nanoparticle concentration was increased from 0.5 to 4%. Addition of nanoparticles enabled separations that were otherwise hindered by extensive adsorption, e.g. separation of GFP mutants differing by only one amino acid. It was also observed that increasing the nanoparticle concentration increased the number of impurities that could be resolved in a GFP sample. This indicates that the adsorption is further reduced, and/or that the nanoparticles provide an interacting pseudostationary phase for electrochromatography.     

Non-standard interaction effects at reactor neutrino experiments

We study non-standard interactions (NSIs) at reactor neutrino experiments, and in particular, the mimicking effects on θ₁₃${\theta }_{13}$. We present generic formulas for oscillation probabilities including NSIs from sources and detectors. Instructive mappings between the fundamental leptonic mixing parameters and the effective leptonic mixing parameters are established. In addition, NSI corrections to the mixing angles θ₁₃${\theta }_{13}$ and θ₁₂${\theta }_{12}$ are discussed in detailed. Finally, we show that, even for a vanishing θ₁₃${\theta }_{13}$, an oscillation phenomenon may still be observed in future short baseline reactor neutrino experiments, such as Double Chooz and Daya Bay, due to the existences of NSIs.     

String model description of polarisation and angular distributions in ¯pp → ¯ΛΛ at low energies

The observed polarisation of Λ hyperons from the inclusive pA → ΛX reaction at high energies has previously been well described within the Lund string model through polarised sˉs quark pair production in the string breaking hadronisation process. This model is here applied to the exclusive ˉpp → ˉΛΛ reaction at low energies and compared to available data sets down to an incident-beam momentum of 1.835 GeV/c. This required an extension of the diquark scattering model to involve three components: an isotropic part relevant close to the threshold, a spectator part and a forward-scattering part as in pA → ΛX at high energies. The observed angular distributions are then reproduced and, for momentum transfers above | t'| = 0.2 GeV², agreement with the measured polarisation is also obtained. Received: 2 April 2002 / Accepted: 24 July 2002 / Published online: 3 December 2002 RID="a" ID="a"Present address: Department of Neutron Research, Uppsala University, Box 525, S-75120 Uppsala, Sweden; e-mail: Stephan.Pomp@tsl.uu.se. RID="b" ID="b"Present address: ESRF, F-38043 Grenoble, France. Communicated by A. Sch?fer