Efficient Tuition Fees, Examinations, and Subsidies (new title: Efficient tuition fees and subsidies)

We assume that students can acquire a wage premium, thanks to studies, and form a rational expectation of their future earnings, which depends on personal "ability". Students receive a private, noisy signal of their ability, and universities can condition admission decisions on the results of noisy tests. We assume first that universities are maximizing social surplus, and contrast the results with those obtained when they are profit maximizers. If capital markets are perfect, and if test results are public knowledge, then the optimal tuition fee is greater than marginal cost, and there is no sorting on the basis of test scores. Students optimally self-select as a result of pricing only. If capital markets are perfect but asymmetries of information are bilateral, i.e., if universities observe a private signal of each student's ability, or if there are borrowing constraints, then the optimal policy involves a mix of pricing and pre-entry selection on the basis of test scores. Optimal tuition can then be set below marginal cost, and can even become negative, if the precision of the university's private assessment of students' abilities is high enough.tuition fees, examinations, state subsidies, higher education, incomplete information

Sharing Budgetary Austerity under Free Mobility and Asymmetric Information: An Optimal Regulation Approach to Fiscal Federalism

In the present article, Tiebout meets Laffont and Tirole in the land of Fiscal Federalism. We use a non-trivial Principal-Multi-Agent model to characterize the optimal intergovernmental grant schedule, when the cost of local public goods depends on hidden characteristics and actions of local governments, and under citizen free mobility. We show that local governments earn informational rents, and how optimal local taxes, public good production levels and land prices are jointly distorted at the second-best optimum, as a consequence of free mobility and asymmetric information. The effect of informational asymmetries is to decrease the average production of public goods and to increase the inter-jurisdictional variance of taxes and public-good production.asymmetric information, Principal-Agent model, public budget deficits, free-mobility equilibrium, fiscal federalism

Sintered aluminium heat pipe (SAHP)

This work is the product of an ongoing PhD project in the School of the Built and Natural Environment of Northumbria University in collaboration with the University of Liverpool and Thermacore Europe Ltd. The achievements at the end of the first year are summarized. The main objective of the project is to develop an aluminum ammonia heat pipe with a sintered wick structure. Currently available ammonia heat pipes mainly use extruded axially grooved aluminum tubes as a capillary wick. There have been a few attempts of employing porous steel or nickel wicks in steel tubes with ammonia as the working fluid (Bai, Lin et al. 2009)although it is a common practice in loop heat pipes but there is no report of aluminum-ammonia heat pipes porous aluminium wick structures. The main barrier is the difficulty of sintering aluminum powders to manufacture porous wicks. So far during this project promising sintered aluminum heat pipe samples have been manufactured using the Selective Laser Melting (SLM) technique with various wick characteristics. This SLM method has proven to be capable of manufacturing very complicated wick structures with different thickness, porosity, permeability and pore sizes in different regions of a heat pipe. In addition the entire heat pipe including the end cap, outer tube wall, wick and the fill tube can be generated in a single process

Enhanced magnetic moment and conductive behavior in NiFe2O4 spinel ultrathin films

Bulk NiFe2O4 is an insulating ferrimagnet. Here, we report on the epitaxial growth of spinel NiFe2O4 ultrathin films onto SrTiO3 single-crystals. We will show that - under appropriate growth conditions - epitaxial stabilization leads to the formation of a spinel phase with magnetic and electrical properties that radically differ from those of the bulk material : an enhanced magnetic moment (Ms) - about 250% larger - and a metallic character. A systematic study of the thickness dependence of Ms allows to conclude that its enhanced value is due to an anomalous distribution of the Fe and Ni cations among the A and B sites of the spinel structure resulting from the off-equilibrium growth conditions and to interface effects. The relevance of these findings for spinel- and, more generally, oxide-based heterostructures is discussed. We will argue that this novel material could be an alternative ferromagetic-metallic electrode in magnetic tunnel junctions.Comment: accepted for publication in Phys. Rev.

Microwave heating-induced DC magnetic flux penetration in YBa2_{2}Cu3_{3}O7−δ_{7-\delta} superconducting thin films

The magneto-optical imaging technique is used to visualize the penetration of the magnetic induction in YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ thin films during surface resistance measurements. The in-situ surface resistance measurements were performed at 7 GHz using the dielectric resonator method. When only the microwave magnetic field $H_{rf}$ is applied to the superconductor, no $H_{rf}$-induced vortex penetration is observed, even at high rf power. In contrast, in the presence of a constant magnetic field superimposed on $H_{rf}$ we observe a progression of the flux front as $H_{rf}$ is increased. A local thermometry method based on the measurement of the resonant frequency of the dielectric resonator placed on the YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ thin film shows that the $H_{rf}$--induced flux penetration is due to the increase of the film temperature.Comment: 6 pages, Journal of Applied Physic