A sharp bilinear cone restriction estimate

The purpose of this paper is to prove an essentially sharp L^2 Fourier restriction estimate for light cones, of the type which is called bilinear in the recent literature.Comment: 38 pages, published versio

The effects of placer mining on the environment in Central Alaska

Within the Tolovana Mining District, as a result of placer mining, 800 acres of land have been disturbed (0.25% of the land area) and 4 million cubic yards of much have been transported down the Tolovana River through the subsiding Minto Flats. This has increased the rate of sedimentation of the lakes adjacent to the Tolovana River. Mine tailings are about 50% revegetated by natural species. Approximately 60 million cubic yards of muck must be removed to mine the Livengood deposits. A large area of settling ponds will be needed if the deposit is stripped by hydraulic means, or a large area for stacking overburden if mechanical stripping is required. The Crooked Creek area, mined for 80 years has 1,900 acres disturbed (0.7% of the land area) and 200,000 cubic yards of much has been stripped. No correlation is apparent between mining and the non-anadromous fish population, although sport fishing is considered by some to be not as good as a result of mining. Portions of the stream system observed to be impacted with mud showed evidence of having been periodically flushed out. Slave analysis and trace element analysis were applied in an attempt to trace sediments back to their sources, but were not successful. Mining is the pioneer industry around which much of the State of Alaska developed. The transportation network required by the mining industry benefits sportsmen, the tour industry, and directly increases the value of adjacent land. The profit from mining brought much of the early population to the state, and will be a steady source of revenue in years to come

A Methodological Note on the Estimation of Programming Models

The paper introduces a general methodological approach for the estimation of constrained optimisation models in agricultural supply analysis. It is based on optimality conditions of the desired programming model and shows a conceptual advantage compared to Positive Mathematical Programming in the context of well posed estimation problems. Moreover, it closes the empirical and methodological gap between programming models and duality based functional models with explicit allocation of fixed factors. Monte Carlo simulations are performed with a maximum entropy estimator to evaluate the functionality of the approach as well as the impact of empirically relevant prior information in small sample situations.Agricultural Supply Analysis, Programming Models, Maximum Entropy Estimation, Prior Information, Research Methods/ Statistical Methods,

A factorization algorithm to compute Pfaffians

We describe an explicit algorithm to factorize an even antisymmetric N^2 matrix into triangular and trivial factors. This allows for a straight forward computation of Pfaffians (including their signs) at the cost of N^3/3 flops.Comment: 6 pages, 1 figure, V2: Minor changes in the text and refs. added, to appear in CP

Spin chain simulations with a meron cluster algorithm

We apply a meron cluster algorithm to the XY spin chain, which describes a quantum rotor. This is a multi-cluster simulation supplemented by an improved estimator, which deals with objects of half-integer topological charge. This method is powerful enough to provide precise results for the model with a theta-term - it is therefore one of the rare examples, where a system with a complex action can be solved numerically. In particular we measure the correlation length, as well as the topological and magnetic susceptibility. We discuss the algorithmic efficiency in view of the critical slowing down. Due to the excellent performance that we observe, it is strongly motivated to work on new applications of meron cluster algorithms in higher dimensions.Comment: 18 pages, 9 figures, published versio

The moderate approach to integrating concurrency and object orientation

Principles of integrating concurrent computation, objects, and inheritance are discussed. The approach outlined here is guided by general considerations about the rôles of the two paradigms being merged. We suggest our approach to some open design questions: the relation of concurrency to inheritance and the thread and synchronisation concept among objects. The question, where should the combination of concurrency and objectorientation be settled between the paradigms, is analysed in different aspects. The presented approach also avoids the inheritance anomaly

Maximal Averages and Packing of One Dimensional Sets

We discuss recent work of several authors on the Kakeya needle problem and other related problems involving nonexistence of small sets containing large families of one dimensional objects

Conference on Alaskan placer mining, focus: gold recovery systems

Alaska Miners' Association and the School of Mineral Industry, University of Alaska, Fairbanks conference proceedings of the Alaskan Placer Mining conference on Gold Recovery Systems