ABSTRACT
In order to simplify the design of representative studies in animal populations the structural differences of animal husbandry (cattle, pigs and laying hens) in Germany were characterised. Several regions were defined and thus districts identified which are typical for the respective region and can be regarded as representatives for the whole region. Data on animal husbandry as well as human population per district originated from the Federal Statistical Office and were linked to the geometric data of the Federal Agency for Cartography and Geodesy. By this, data of "livestock units/square kilometre area" and "farms/square kilometre area" per district were calculated using methods of the spatial statistics Global Moran's Index, Anselin Local Moran's Index and Getis-Ord Gi*. With the help of these analyses six clusters could be identified which resulted in four large (Middle, Northwest, East, and South) and one smaller region (Northern Upper-Rhine) respecting the federal state borders. These regions differed significantly regarding animal and farm densities. The selection of typical districts was carried out with the help of the respective animal and farm data of the species pigs, dairy cattle and laying hens. The means of the selected districts (three to six per region) were within the 60%- and the 80%-percentile of at least two of the analysed variables. Concerning the region Northern Upper-Rhine no representative district was selected. This presented regionalisation including representative districts can be used for the design of scientific studies that are associated with animal husbandry in Germany.
Subject(s)
Animal Husbandry/organization & administration , Animal Husbandry/statistics & numerical data , Livestock , Animals , Cattle , Chickens , Cluster Analysis , Dairying , Germany , Population Density , Sheep , SwineABSTRACT
We develop a Monte Carlo wave function algorithm for the quantum linear Boltzmann equation, a Markovian master equation describing the quantum motion of a test particle interacting with the particles of an environmental background gas. The algorithm leads to a numerically efficient stochastic simulation procedure for the most general form of this integrodifferential equation, which involves a five-dimensional integral over microscopically defined scattering amplitudes that account for the gas interactions in a nonperturbative fashion. The simulation technique is used to assess various limiting forms of the quantum linear Boltzmann equation, such as the limits of pure collisional decoherence and quantum Brownian motion, the Born approximation, and the classical limit. Moreover, we extend the method to allow for the simulation of the dissipative and decohering dynamics of superpositions of spatially localized wave packets, which enables the study of many physically relevant quantum phenomena, occurring e.g., in the interferometry of massive particles.
ABSTRACT
We use quantum diffusive trajectories to prove that the time evolution of two-qubit entanglement under spontaneous emission can be fully characterized by optimal continuous monitoring. We analytically determine this optimal unraveling and derive a deterministic evolution equation for the system's concurrence. Furthermore, we propose an experiment to monitor the entanglement dynamics in bipartite two-level systems and to determine the disentanglement time from a single trajectory.
ABSTRACT
We show that, for experimentally relevant systems, there is an optimal measurement strategy to monitor the time evolution of entanglement under open system dynamics. This suggests an efficient, dynamical characterization of the entanglement of composite, open quantum systems.
