Ultrahigh energy neutrino scattering: an update

We update our estimates of charged and neutral current neutrino total cross sections on isoscalar nucleons at ultrahigh energies using a global (x, Q^2) fit, motivated by the Froissart bound, to the F_2 (electron-proton) structure function utilizing the most recent analysis of the complete ZEUS and H1 data sets from HERA I. Using the large Q^2, small Bjorken-x limits of the "wee" parton model, we connect the ultrahigh energy neutrino cross sections directly to the large Q^2, small-x extrapolation of our new fit, which we assume saturates the Froissart bound. We compare both to our previous work, which utilized only the smaller ZEUS data set, as well as to recent results of a calculation using the ZEUS-S based global perturbative QCD parton distributions using the combined HERA I results as input. Our new results substantiate our previous conclusions, again predicting significantly smaller cross sections than those predicted by extrapolating pQCD calculations to neutrino energies above 10^9 GeV.Comment: 8 pages, 1 figure, 3 table

Modulation of social behavior by the agouti pigmentation gene

Agouti is a secreted neuropeptide that acts as an endogenous antagonist of melanocortin receptors. Mice and rats lacking agouti (called non-agouti) have dark fur due to a disinhibition of melanocortin signaling and pigment deposition in the hair follicle. Non-agouti animals have also been reported to exhibit altered behavior, despite no evidence for the expression of agouti outside the skin. Here we confirm that non-agouti mice show altered social behavior and uncover expression of agouti in the preputial gland, a sebaceous organ in the urinary tract that secretes molecules involved in social behavior. Non-agouti mice had enlarged preputial glands and altered levels of putative preputial pheromones and surgical removal of the gland reversed the behavioral phenotype. These findings demonstrate the existence of an autologous, out-of-skin pathway for the modulation of social behavio

Bloch-mode analysis for retrieving effective parameters of metamaterials

We introduce a new approach for retrieving effective parameters of metamaterials based on the Bloch-mode analysis of quasi-periodic composite structures. We demonstrate that, in the case of single-mode propagation, a complex effective refractive index can be assigned to the structure, being restored by our method with a high accuracy. We employ both surface and volume averaging of the electromagnetic fields of the dominating (fundamental) Bloch modes to determine the Bloch and wave impedances, respectively. We discuss how this method works for several characteristic examples, and demonstrate that this approach can be useful for retrieval of both material and wave effective parameters of a broad range of metamaterials.Comment: 12 pages, 10 figure

Modeling and optimal control of an energy-efficient hybrid solar air conditioning system

© 2014 Elsevier B.V. All rights reserved. The paper addresses the modeling and optimal control problem of a new hybrid solar-assisted air conditioning system developed for performance enhancement and energy efficiency improvement. To regulate the mass flow rate of the refrigerant vapor passing through a water storage tank for increasing the refrigerant's sub-cooling process at partial loads, we propose a new discharge bypass line together with an inline solenoid valve, installed after the compressor. In addition, to control the air flow rate, a variable speed drive is coupled with the condenser fan. For the control purpose, a lumped parameter model is first developed to describe the system dynamics in an explicit input-output relationship; then, a linear optimal control scheme is applied for the system's multivariable control. The system has been fully-instrumented to examine its performance under different operation conditions. The system model is then validated by extensive experimental tests. Based on the obtained dynamic model, an optimal controller is designed to minimize a quadratic cost function. Numerical algorithms, implemented in a simulation tool, are then employed to predict the energy performance of the system under transient loads. The experimental results obtained from implementation with PLC demonstrate that the newly-developed system can deliver higher system efficiency owing to amelioration of the refrigeration effect in the direct expansion evaporator and adjustment of its air flow rate. The development is thus promising for improvement of energy efficiency, enhancement of the system performance while fulfilling the cooling demand