On the Dissection of Rectangles into Right-Angled Isosceles Triangles

AbstractWe consider the problem of dissecting a rectangle or a square into unequal right-angled isosceles triangles. This is regarded as a generalization of the well-known and much-solved problem of dissecting such figures into unequal squares. There is an analogous “electrical” theory but it is based on digraphs instead of graphs and has an appropriate modification of Kirchhoff's first law. The operation of reversing all edges in the digraph is found to be of great help in the construction of “perfect” dissected squares

Finding a state in a haystack

We consider the problem to single out a particular state among $2^n$ orthogonal pure states. As it turns out, in general the optimal strategy is not to measure the particles separately, but to consider joint properties of the $n$-particle system. The required number of propositions is $n$. There exist $2^n!$ equivalent operational procedures to do so. We enumerate some configurations for three particles, in particular the Greenberger-Horne-Zeilinger (GHZ)- and W-states, which are specific cases of a unitary transformation For the GHZ-case, an explicit physical meaning of the projection operators is discussed.Comment: 11 page

Behavioral and Welfare Effects of Tournaments and Fixed Performance Contracts: Some Experimental Evidence

Using experimental economics, we compare the efficiency and welfare effects of tournaments and fixed performance contracts. Our subjects (agents) were generally better off under fixed performance contracts, but the advantage of the fixed performance contract disappears if the relative magnitude of the standard deviation of the common shock exceeds a critical value. Efficiency wise, agents tend to exert higher effort under fixed performance contracts, on average. Additionally, an increase in the common shock standard deviation appeared to be associated with lower effort under tournaments. Our results shed light on the potential impact of legislative proposals to ban tournament contracts. Copyright 2005, Oxford University Press.

Determinants and current flows in electric networks

AbstractWe consider electrical networks in which current enters at a single node and leaves at another. It has long been known that the currents and potential differences in such networks can be expressed in terms of determinants, or alternatively as counts of trees. Here we give alternative determinantal expressions

Characterization of an energy dispersive X-ray fluorescence imaging system based on a Micropattern Gaseous Detector

An Energy Dispersive X-ray Fluorescence (EDXRF) imaging system based on a Micropattern Gas Detector has already shown good results for di erent applications. An X-ray tube, a pinhole camera and a Micro-Hole and Strip Plate (MHSP) based detector are the main components of the experimental system. The detector uses an MHSP in a Xe atmosphere at 1 bar, acting as a photon counting device, i.e., it is capable to record each single event retaining the energy and the interaction position (2D-sensitive detector) information of the incident photon, demonstrating to be a promising device for EDXRF imaging applications. This work presents studies of energy resolution, energy linearity and spatial resolution/elemental mapping as a function of image magni cation of the system