The effect of planting date on yield was studied in Parana State, Brazil where five tropical hybrids of maize were planted at 14 planting dates over three growing seasons at five locations. Soil water holding characteristics and meteorological variables were measured at each location. The water release curve for each soil was determined, using a power function. Corn heat units were calculated and used to measure the phenological development of each hybrid. This information, along with meteorological data, was used in a mathematical model to simulate plant growth over each growing period. Meteorological data from 1976 to 1986 were employed to simulate yield data for 14 planting dates during each growing season at four locations for each hybrid. The average production curve for the 10 growing seasons was compared to the curve observed for the 1986/87 growing season for three of the five hybrids. Thermal requirements appeared as an efficient tool to predict corn developmental stages, and the power function fit satisfactorily the observed soil data. The predicted curve, representing a 10-year average, showed that the designed model accounted for the major cultural and environmental factors that affect yield at each location, being sensitive enough to detect differences among genotypes. Comparisons between predicted and observed curves showed that they had the same shape.

The study of the speed of human reactions is older than experimental psychology. Starting in the early 1800's as the study of the "personal equation" in astronomy, it became known as "mental chronometry" in psychological laboratories of the late 19th Century (Boring, 1950). The time elapsing between the presentation of a predetermined signal and the occurrence of a predetermined response served as a measure of reaction speed. This measure, reaction time or response latency, was studied in relation to several variables (e.g., preparation, attention, signal modality) by the early investigators. [...]

A performance evaluation of CSTC (Cooperative Space Time Coding) with spatially cor-related fading and imperfect channel estimation in Gaussian as well as impulsive noise is presented. Closed form expressions for the pairwise error probability conditioned on the estimated channel gains are derived by assuming the components of the received vector are independent given the estimated channel gains. An expurgated union bound using the limiting before averaging technique given the estimated channel gains is then obtained. Although this assumption is not strictly valid, simulation results show that the bound is accurate in estimating the diversity order as long the channel estimation is not very poor. It is found that CSTC with block fading channels can reduce the frame error rate (FER) relative to SUSTC (Single User Space Time Coding) with quasi-static fading channels, even when the channel gains for each user are strongly correlated and when the channel estimations are very poor. A decision metric for CSTC with spatially correlated fading, imperfect channel estimation, and impulsive mixture Gaussian noise is derived which yields lower FERs than the Gaussian noise decision metric. Simulation results show that the FER performance of CSTC with mixture Gaussian noise outperforms CSTC with Gaussian noise at low SNR. At high SNR, the FER performance of CSTC with Gaussian noise is better than the FER performance of CSTC with mixture Gaussian noise due to the heavy tail of the mixture Gaussian noise.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.