8,805 research outputs found
Optimal trading strategies - a time series approach
Motivated by recent advances in the spectral theory of auto-covariance
matrices, we are led to revisit a reformulation of Markowitz' mean-variance
portfolio optimization approach in the time domain. In its simplest incarnation
it applies to a single traded asset and allows to find an optimal trading
strategy which - for a given return - is minimally exposed to market price
fluctuations. The model is initially investigated for a range of synthetic
price processes, taken to be either second order stationary, or to exhibit
second order stationary increments. Attention is paid to consequences of
estimating auto-covariance matrices from small finite samples, and
auto-covariance matrix cleaning strategies to mitigate against these are
investigated. Finally we apply our framework to real world data
ESTIMATION OF EMPLOYMENT MULTIPLIERS FOR PLANNING IN OZARKS NONMETROPOLITAN COUNTIES
Labor and Human Capital,
Experiments on the large-scale structure of turbulence in the near-jet region
The near region of an axisymmetric, turbulent jet was investigated. Turbulence quantities, as well as mean velocities, were measured between 3 and 23 diam away from the nozzle. The mean velocity profiles were similar over most of this distance, whereas the turbulence quantities were far from equilibrium conditions. Across the jet, the rate of large-scale turbulence varied considerably; however, a Strouhal number based on local velocity, the diameter of the jet, and the frequency of the large-scale turbulent oscillation remained relatively constant. The formation of the initial instability waves and the pairing of the vortices were examined. Turbulent fluctuations were observed only downstream of the pairing process
QCD Corrections to Hadronic Z and tau Decays
We present a brief (mainly bibliographical) report on recently performed
calculations of terms of order O(\alpha_s^4 n_f^2) and O(\alpha_s^4 n_f^2
m_q^2) for hadronic Z and \tau decay rates. A few details about the analytical
evaluation of the masters integrals appearing in the course of calculations are
presented.Comment: revised version (some references corrected); 3 pages, talk given at
International Europhysics Conference on High Energy Physics, Aachen, Germany,
17-23 July 200
Analyzing the feasibility of domestic rural water supplies in Missouri with emphasis on the Ozarks region
Cover title."Agricultural Experiment Station, University of Missouri-Columbia, in cooperation with Economics, Statistics, and Cooperatives Service, U.S. Department of Agriculture."Includes bibliographical references
Lentic and Lotic Habitats as Templets for Fungal Communities: Traits, Adaptations, and Their Significance to Litter Decomposition Within Freshwater Ecosystems
Decomposition of plant matter is a key ecosystem process and considerable research has examined plant litter decay processes in freshwater habitats. Fungi are common inhabitants of the decomposer microbial community and representatives of all major fungal phyla have been identified within freshwater systems. Development and application of quantitative methods over the last several decades have firmly established that fungi are central players in the decomposition of plant litter in freshwaters and are important mediators of energy and nutrient transfer to higher trophic levels. Despite the critical roles that fungi play in carbon and nutrient cycling in freshwater ecosystems, there are notable differences in the types and adaptations of fungal communities between lotic and lentic habitats. These differences can be explained by the wide range of hydrologic, physical, chemical and biological conditions within freshwater systems, all of which can influence the presence, type, and activity of fungal decomposers and their impact on litter decomposition. This paper seeks to provide a brief overview of the types, adaptations, and role of fungi within lotic and lentic freshwater ecosystems, with a particular emphasis on their importance to litter decomposition and the key environmental conditions that impact their growth and decay activities. This discussion will specifically focus on fungal dynamics occurring on plant litter in forested headwater streams and emergent freshwater marshes, since published data concerning their role in these systems is considerably more abundant in comparison to other freshwater habitats
Optimal Location of the U.S. Broiler Industry
Livestock Production/Industries, Marketing, Productivity Analysis,
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