48 research outputs found
Nutrients in Wastewater from a Phosphate Fertilizer Manufacturing Plant Stored for Irrigation
Wastewater from a fertilizer manufacturing plant in southern Idaho
was pumped into a storage impoundment during the winter months and stored
for irrigating and fertilizing agricultural crops the next summer. Analyses of
water samples from the impoundment taken monthly showed the following
mean annual nutrient concentrations: Total Kjeldahl Nitrogen (TKN) 94,
NH+4-N 61, NO-3–N 8, total P 17, ortho P 15, and K 17 mg/L. The impoundment
surface area averaged 10.5 ha with a maximum pond volume during the
year of 362,000 m3 . Accumulated nutrients in the impounded wastewater
available for irrigating and fertilizing agricultural crops at the beginning of the
growing season was TKN 30.2, NH+4–N 23.2, NO3-N 4.3, total P 9.7, and K 6.2
metric tons. Nitrification in the pond was minimal. Redox potentials were
between 480 and 500 mv at all depths and locations measured in the pond in
the summer and denitrification was minimal. The redox potential indicated that
the water was near oxygen saturation
Path integrals approach to resisitivity anomalies in anharmonic systems
Different classes of physical systems with sizeable electron-phonon coupling
and lattice distortions present anomalous resistivity behaviors versus
temperature. We study a molecular lattice Hamiltonian in which polaronic charge
carriers interact with non linear potentials provided by local atomic
fluctuations between two equilibrium sites. We study a molecular lattice
Hamiltonian in which polaronic charge carriers interact with non linear
potentials provided by local atomic fluctuations between two equilibrium sites.
A path integral model is developed to select the class of atomic oscillations
which mainly contributes to the partition function and the electrical
resistivity is computed in a number of representative cases. We argue that the
common origin of the observed resistivity anomalies lies in the time retarded
nature of the polaronic interactions in the local structural instabilities.Comment: 4 figures, to appear in Phys.Rev.B, May 1st (2001
Diverse Beliefs and Time Variability of Risk Premia
Why do risk premia vary over time? We examine this problem theoretically and empirically by studying the effect of market belief on risk premia. Individual belief is taken as a fundamental primitive state variable. Market belief is observable; it is central to the empirical evaluation and we show how to measure it. Our asset pricing model is familiar from the noisy REE literature but we adapt it to an economy with diverse beliefs. We derive equilibrium asset prices and implied risk premium. Our approach permits a closed form solution of prices; hence we trace the exact effect of market belief on the time variability of asset prices and risk premia. We test empirically the theoretical conclusions. Our main result is that, above the effect of business cycles on risk premia, fluctuations in market belief have significant independent effect on the time variability of risk premia. We study the premia on long positions in Federal Funds Futures, 3- and 6-month Treasury Bills (T-Bills). The annual mean risk premium on holding such assets for 1-12 months is about 40-60 basis points and we find that, on average, the component of market belief in the risk premium exceeds 50% of the mean. Since time variability of market belief is large, this component frequently exceeds 50% of the mean premium. This component is larger the shorter is the holding period of an asset and it dominates the premium for very short holding returns of less than 2 months. As to the structure of the premium we show that when the market holds abnormally favorable belief about the future payoff of an asset the market views the long position as less risky hence the risk premium on that asset declines. More generally, periods of market optimism (i.e. "bull" markets) are shown to be periods when the market risk premium is low while in periods of pessimism (i.e. "bear" markets) the market's risk premium is high. Fluctuations in risk premia are thus inversely related to the degree of market optimism about future prospects of asset payoffs. This effect is strong and economically very significant
Fogo e dinâmica da comunidade lenhosa em cerrado sentido restrito, Barra do Garças, Mato Grosso
Autoecologia das espécies florestais em regime de plantio de enriquecimento em linha na floresta primária da Amazônia Central
Nutrients in Wastewater from a Phosphate Fertilizer Manufacturing Plant Stored for Irrigation
Wastewater from a fertilizer manufacturing plant in southern Idaho
was pumped into a storage impoundment during the winter months and stored
for irrigating and fertilizing agricultural crops the next summer. Analyses of
water samples from the impoundment taken monthly showed the following
mean annual nutrient concentrations: Total Kjeldahl Nitrogen (TKN) 94,
NH+4-N 61, NO-3–N 8, total P 17, ortho P 15, and K 17 mg/L. The impoundment
surface area averaged 10.5 ha with a maximum pond volume during the
year of 362,000 m3 . Accumulated nutrients in the impounded wastewater
available for irrigating and fertilizing agricultural crops at the beginning of the
growing season was TKN 30.2, NH+4–N 23.2, NO3-N 4.3, total P 9.7, and K 6.2
metric tons. Nitrification in the pond was minimal. Redox potentials were
between 480 and 500 mv at all depths and locations measured in the pond in
the summer and denitrification was minimal. The redox potential indicated that
the water was near oxygen saturation