ECONOMETRIC METHODOLOGY II : STRENGTHENING TIME SERIES ANALYSIS

This article reviews some of the recent methodology developed for the analysis of time series data stressing that the statistical properties of the individual series need to be analysed to avoid spurious regressions. A convergence of econometric methodology is entertained with specific focus on cointegration and error correction models which allows the testing of long run relationships between variables and allows for a more dynamic structure than some of the previous models that appear in the literature. An example of this is the commonly used partial adjustment model in supply analysis which is nested in the less restrictive error correction model. Tests can be performed on the validity of these restrictions. These models have a wide application in agricultural economic analysis.Research Methods/ Statistical Methods,

An initial assessment of the performance achieved by the Seasat-1 radar altimeter

The results of an initial on-orbit engineering assessment of the performance achieved by the radar altimeter system flown on SEASAT-1 are presented. Additionally, the general design characteristics of this system are discussed and illustrations of altimeter data product are provided. The instrument consists of a 13.5 GHz monostatic radar system that tracks in range only using a one meter parabolic antenna pointed at the satellite nadir. Two of its unique features are a linear FM transmitter with 320 MHz bandwidth which yields a 3.125 nanosecond time delay resolution, and microprocessor implemented closed loop range tracking, automatic gain control (AGC), and real time estimation of significant wave height (SWH). Results presented show that the altimeter generally performed in accordance with its orginal performance requirments of measuring altitude to a precision of less the 10 cm RMS, significant wave height to an accuracy of + or - 0.5 m or 10%, whichever is greater, and ocean backscatter coefficient to an accuracy of + or - 1 db, all over an SWH range of 1 to 20 meters

Production Incentives for Small Scale Farmers in Zimbabwe: The Case of Cotton and Maize

The paper presents an empirical investigation of the production response of small scale producers of maize and cotton for communal agriculture in Zimbabwe. The error correction model, which employs the concept of cointegration to avoid spurious regressions, is used in the analysis. The factors affecting maize output were the price of maize relative to seed, the number of marketing depots established in the communal areas and the number of loans provided to these farmers. The factors affecting cotton output were the increase in communal lands due to the resettlement program, the number of loans extended to small scale farmers and the price of cotton relative to seed. The weather played the most significant role in determining the quantity of maize sold.Agricultural and Food Policy, Crop Production/Industries,

Estimation of the rate of return to wine grape research and technology development expenditures in South Africa

This article evaluates the impact of research and technology development in the wine grape industry in order to determine the rate of return (ROR) to these investments, and to make specific recommendations on funding. The analysis illustrates the applied and adaptive nature of the research conducted in the industry, with RORs of roughly 40 percent for R&D and extension. This is high, providing excellent motivation for increased investment in R&D.Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,

Deployment mechanisms on Pioneer Venus probes

Deployment mechanisms were developed to position scientific instruments during probe descent into the Venus atmosphere. Each mechanism includes a provision for pyrotechnic release of the enclosure door, negator springs for positive deployment torque, and an active damper using a shunted dc motor. The deployment time requirement is under 2 seconds, and the deployment shock must be less than 100 g's. The mechanism is completely dry lubricated and constructed mainly of titanium for high strength and high temperature stability. The mechanism was qualified for descent decelerations up to 565 g's and for instrument alignment up to 940 F. The mechanism requirements, the hardware design details, the analytical simulations, and the qualification testing are described

Following the relaxation dynamics of photoexcited aniline in the 273-266 nm region using time-resolved photoelectron imaging

Scanning tunnelling microscopy (STM) and Auger electron spectroscopy (AES) have been used to investigate the growth morphology of ultra-thin Pb films on the Ni3Al(111) face at room temperature. A previous study [K. Miśków and A. Krupski Appl Surf Sci 273, 2013, 554] using low-energy electron diffraction (LEED) and real time Auger intensity recording has demonstrated that an initial two-dimensional growth of the first Pb monolayer thick ‘wetting layer’ takes place. With further deposition and for T = 300 K, flat three atomic-layer-high islands are grown. Above 350 K, the Stranski–Krastanov growth mode was observed. In the current study, the analysis of STM measurements indicate and confirm that for coverage θ = 1.0 ML two-dimensional growth of the first Pb monolayer took place. Above θ > 1.0 ML, a three-dimensional growth of the Pb islands was observed with a strongly preferred atomic-scale ‘magic height (N),’ hexagonal shape and flat-tops. At coverage θ = 3.5 ML, only islands containing N = 3, 5, 7 and 11 atomic layers of Pb are observed. At the higher coverage θ = 5.5 ML, three types of regular hexagonal islands with side lengths of 25, 30 and 45 nm are observed. Furthermore, three different island adsorption configurations rotated by 10° ± 1° and 30° ± 6° with respect to each other were observed. After an annealing at T = 400 K of 5.5 ML of lead deposited at RT on the Ni3Al(111) the morphology of the surface changes. Post-anneal, islands of Pb are observed above the ‘wetting layer’ with an estimated average size and diameter of 768 ± 291 nm2 and 38.17 ± 6.56 nm and constant uniform height of two atomic layers (N = 2)

Demand for livestock tick control service in the Venda region, Northern Province

This article analyses factors influencing farmers’ willingness-to-pay for dipping services, as well as the revealed preference for dipping frequency using the multivariate and the logistic regression models. The study is based on a cross sectional survey of 125 smallscale cattle farmers interviewed in the Venda region of the Northern Province. Empirical multivariate and the logistic regression analysis show that liquidity, human resource, satisfaction with the programme and structure of production significantly influences farmers’ willingness-to-pay. However, the most important factor influencing both the willingness-to-pay and the dipping frequency is liquidity (employment). The results of this study have important implications for the delivery of veterinary services particularly in developing regions.Livestock Production/Industries,

D=5 Einstein-Maxwell-Chern-Simons Black Holes

5-dimensional Einstein-Maxwell-Chern-Simons theory with Chern-Simons coefficient $\lambda=1$ has supersymmetric black holes with vanishing horizon angular velocity, but finite angular momentum. Here supersymmetry is associated with a borderline between stability and instability, since for $\lambda>1$ a rotational instability arises, where counterrotating black holes appear, whose horizon rotates in the opposite sense to the angular momentum. For $\lambda>2$ black holes are no longer uniquely characterized by their global charges, and rotating black holes with vanishing angular momentum appear.Comment: 4 pages, 4 figures, RevTeX styl

Transport model of nucleon-nucleus reaction

A simplified model of nucleon-nucleus reaction is developed and some of its properties are examined. Comparisons with proton production measured for targets of Al-27, Ni-58, Zr-90, and Bi-209 show some hope for developing an accurate model for these complex reactions. It is suggested that binding effects are the next step required for further development