Farm Diversification in Relation to Landscape Properties

Current European Common Agricultural Policy (CAP) has been moving from production support subsidies to direct decoupled income support. The emergence in policy making of the concept of multifunctional agriculture leads to the recognition that a farmer produces more than food: he produces jointly both commodity and non-commodity goods. Environmental contracts were developed in order to encourage the provision of non-commodity goods such as landscape or biodiversity. Next to these contracts, other activities as for example recreation can be observed. They are the result of farm diversification. The role of location in farmers’ decision making to diversify is pointed out in literature but geographical information is generally reduced to the location within a political delimitation unit the empirical work. Objective of this paper is two-fold. Firstly, it addresses the role of location, in term of site specific natural conditions as well as neighbouring emerging dynamics in farmer’s decision making to diversify. Attention is paid to number of activities as well as the specific types of activities, notably green services, daily recreation and other farm-linked services. Secondly, this paper introduces income from agriculture explicitly allowing testing short term price sensitivity. It was found that attractive landscape is a driver for diversification as these landscape offer more opportunities. Furthermore, diversification is responsive to price. Thirdly, role of density of past multifunctional activities in the neighborhood influences farm diversification: multifunctional activities create an externality effects as new activities emerge next to already existing ones. This dynamic may lead to the emergence of ‘multifunctional hotspots’ in landscape.Farmer diversification, landscape services, location, Farm Management, Land Economics/Use,

Board of Regents of University of Oklahoma v. National Collegiate Athletic Association, Application of the Per Se Rule to Price-Fixing Agreements

In Board of Regents of University of Oklahoma v. National Collegiate Athletic Association, the Tenth Circuit Court of Appeals affirmed a lower court ruling that invalidated regulation of college football television contracts by the National Collegiate Athletic Association (NCAA). This decision left colleges and universities free to contract for the sale of broadcast rights to their football games. The United States District Court for the Western District of Oklahoma held that the NCAA television foot- ball plan and network contracts constituted an illegal price-fixing agreement and thus were per se violations of section 1 of the Sherman Anti-Trust Act. The Tenth Circuit Court of Appeals affirmed the holding that the NCAA regulations were illegal per se and, under the rule of reason analysis of the Sherman Anti-Trust Act, also found the regulations to be unreasonably restrictive of competitive conditions

Simulation of braiding anyons using Matrix Product States

Anyons exist as point like particles in two dimensions and carry braid statistics which enable interactions that are independent of the distance between the particles. Except for a relatively few number of models which are analytically tractable, much of the physics of anyons remain still unexplored. In this paper, we show how U(1)-symmetry can be combined with the previously proposed anyonic Matrix Product States to simulate ground states and dynamics of anyonic systems on a lattice at any rational particle number density. We provide proof of principle by studying itinerant anyons on a one dimensional chain where no natural notion of braiding arises and also on a two-leg ladder where the anyons hop between sites and possibly braid. We compare the result of the ground state energies of Fibonacci anyons against hardcore bosons and spinless fermions. In addition, we report the entanglement entropies of the ground states of interacting Fibonacci anyons on a fully filled two-leg ladder at different interaction strength, identifying gapped or gapless points in the parameter space. As an outlook, our approach can also prove useful in studying the time dynamics of a finite number of nonabelian anyons on a finite two-dimensional lattice.Comment: Revised version: 20 pages, 14 captioned figures, 2 new tables. We have moved a significant amount of material concerning symmetric tensors for anyons --- which can be found in prior works --- to Appendices in order to streamline our exposition of the modified Anyonic-U(1) ansat

Full- & Reduced-Order State-Space Modeling of Wind Turbine Systems with Permanent-Magnet Synchronous Generator

Wind energy is an integral part of nowadays energy supply and one of the fastest growing sources of electricity in the world today. Accurate models for wind energy conversion systems (WECSs) are of key interest for the analysis and control design of present and future energy systems. Existing control-oriented WECSs models are subject to unstructured simplifications, which have not been discussed in literature so far. Thus, this technical note presents are thorough derivation of a physical state-space model for permanent magnet synchronous generator WECSs. The physical model considers all dynamic effects that significantly influence the system's power output, including the switching of the power electronics. Alternatively, the model is formulated in the $(a,b,c)$- and $(d,q)$-reference frame. Secondly, a complete control and operation management system for the wind regimes II and III and the transition between the regimes is presented. The control takes practical effects such as input saturation and integral windup into account. Thirdly, by a structured model reduction procedure, two state-space models of WECS with reduced complexity are derived: a non-switching model and a non-switching reduced-order model. The validity of the models is illustrated and compared through a numerical simulation study.Comment: 23 pages, 11 figure

Broadband high-resolution x-ray frequency combs

Optical frequency combs have had a remarkable impact on precision spectroscopy. Enabling this technology in the x-ray domain is expected to result in wide-ranging applications, such as stringent tests of astrophysical models and quantum electrodynamics, a more sensitive search for the variability of fundamental constants, and precision studies of nuclear structure. Ultraprecise x-ray atomic clocks may also be envisaged. In this work, an x-ray pulse-shaping method is put forward to generate a comb in the absorption spectrum of an ultrashort high-frequency pulse. The method employs an optical-frequency-comb laser, manipulating the system's dipole response to imprint a comb on an excited transition with a high photon energy. The described scheme provides higher comb frequencies and requires lower optical-comb peak intensities than currently explored methods, preserves the overall width of the optical comb, and may be implemented by presently available x-ray technology

Ideal Bose gas in fractal dimensions and superfluid 4^4He in porous media

Physical properties of ideal Bose gas with the fractal dimensionality between D=2 and D=3 are theoretically investigated. Calculation shows that the characteristic features of the specific heat and the superfluid density of ideal Bose gas in fractal dimensions are strikingly similar to those of superfluid Helium-4 in porous media. This result indicates that the geometrical factor is dominant over mutual interactions in determining physical properties of Helium-4 in porous media.Comment: 13 pages, 6 figure