254 research outputs found
Measurement and analysis of rural household income in a dualistic economy: The case of South Africa
Government Departments in South Africa utilise a number of different data sets on income of rural households. These include the Population Census, the October Household Survey of 1995 and 2000, the Rural Household Survey of 1997 and the various agricultural censuses (1996 and 2003). All of these use different approaches in obtaining household income. The agricultural census, for example, only reports on farm income – excluding the non-farm income. This paper reviews the different sources of household income data, their measurement techniques and the utilisation thereof. The difference in application of various surveys in the former homeland areas and the so-called commercial farming areas are also shown. In the case of the former homeland areas integrated rural household data are used for poverty measurement purposes. The context and methodologies of these surveys are discussed in detail.Consumer/Household Economics,
What About Continuous Corn?
Interest in continuous corn in Iowa has been g rowing for several years. And increasing numbers of farmers have been trying it out on their own. Here\u27s a report on the results of our Iowa tests with continuous corn
Principles and methods of wind-erosion control in Iowa
Wind erosion in Iowa has been increasing in frequency and intensity with the increase in acreage of row crops and consequent increase in fall-plowed acres. This erosion has attracted widespread attention because blowing dust has created a hazard to health and safety. This bulletin is a report of research conducted in areas where wind erosion has been a problem for many years and the application of the findings in Iowa.https://lib.dr.iastate.edu/specialreports/1058/thumbnail.jp
The influence of nitrogen and phosphorus ferilization on nutrient status and profitability of Bromegrass on Ida soils
This study was undertaken to determine the profitability and the feasibility of fertilizing bromegrass for grazing in the Monona-Ida-Hamburg soil association area. This area is well adapted to growing forage crops. Because of the high content of calcium and potassium, alfalfa grows well if phosphorus is applied. Bromegrass is able in some way to get nitrogen from alfalfa, and the two crops grow well together. The bloat danger in pasturing alfalfa or bromegrass-alfalfa mixtures, however, is well known to cattlemen in the area. Many believe the cost of nitrogen fertilizer to maintain productivity of bromegrass pastures is less than the cost of losses from bloat on bromegrass-alfalfa pastures.
The profitability of fertilizing bromegrass stands is examined in Part I of the study. The feasibility is examined in Part II. In Part I, returns at three levels of nitrogen cost and beef price and at three conversion ratios of forage to beef are calculated on the basis of experimental yields
Absolute frequency measurement of the magnesium intercombination transition
We report on a frequency measurement of the clock
transition of Mg on a thermal atomic beam. The intercombination
transition has been referenced to a portable primary Cs frequency standard with
the help of a femtosecond fiber laser frequency comb. The achieved uncertainty
is which corresponds to an increase in accuracy of six
orders of magnitude compared to previous results. The measured frequency value
permits the calculation of several other optical transitions from to
the -level system for Mg, Mg and Mg. We describe in
detail the components of our optical frequency standard like the stabilized
spectroscopy laser, the atomic beam apparatus used for Ramsey-Bord\'e
interferometry and the frequency comb generator and discuss the uncertainty
contributions to our measurement including the first and second order Doppler
effect. An upper limit of in one second for the short term
instability of our optical frequency standard was determined by comparison with
a GPS disciplined quartz oscillator.Comment: 8 pages, 8 figure
-BaBO deep UV monolithic walk-off compensating tandem
The generation of watt-level cw narrow-linewidth sources at specific deep UV
wavelengths corresponding to atomic cooling transitions usually employs
external cavity-enhanced second-harmonic generation (SHG) of moderate-power
visible lasers in birefringent materials. In this work, we investigate a novel
approach to cw deep-UV generation by employing the low-loss BBO in a monolithic
walkoff-compensating structure [Zondy {\it{et al}}, J. Opt. Soc. Am. B
{\bf{20}} (2003) 1675] to simultaneously enhance the effective nonlinear
coefficient while minimizing the UV beam ellipticity under tight focusing. As a
preliminary step to cavity-enhanced operation, and in order to apprehend the
design difficulties stemming from the extremely low acceptance angle of BBO, we
investigate and analyze the single-pass performance of a mm monolithic
walk-off compensating structure made of 2 optically-contacted BBO plates cut
for type-I critically phase-matched SHG of a cw nm dye laser. As
compared with a bulk crystal of identical length, a sharp UV efficiency
enhancement factor of 1.65 has been evidenced with the tandem structure, but at
nm from the targeted fundamental wavelength, highlighting the
sensitivity of this technique when applied to a highly birefringent material
such as BBO. Solutions to angle cut residual errors are identified so as to
match accurately more complex periodic-tandem structure performance to any
target UV wavelength, opening the prospect for high-power, good beam quality
deep UV cw laser sources for atom cooling and trapping.Comment: 21 pages, 8 figures, to appear in Opt. Commu
Soils Survey of Spink County South Dakota
This soil survey report with its accompanying map presents information about the soils, crops, and agriculture of Spink County. It also deals briefly with such related topics as topography and cultural features. This soil survey is designed to meet the needs of a wide variety of readers. The following paragraphs indicate the sections of interest to persons concerned with specific tracts of land, to those concerned with the county as a whole, and to students and teachers of soil science and related agricultural subjects
A New Independent Limit on the Cosmological Constant/Dark Energy from the Relativistic Bending of Light by Galaxies and Clusters of Galaxies
We derive new limits on the value of the cosmological constant, ,
based on the Einstein bending of light by systems where the lens is a distant
galaxy or a cluster of galaxies. We use an amended lens equation in which the
contribution of to the Einstein deflection angle is taken into
account and use observations of Einstein radii around several lens systems. We
use in our calculations a Schwarzschild-de Sitter vacuole exactly matched into
a Friedmann-Robertson-Walker background and show that a -contribution
term appears in the deflection angle within the lens equation. We find that the
contribution of the -term to the bending angle is larger than the
second-order term for many lens systems. Using these observations of bending
angles, we derive new limits on the value of . These limits constitute
the best observational upper bound on after cosmological constraints
and are only two orders of magnitude away from the value determined by those
cosmological constraints.Comment: 5 pages, 1 figure, matches version published in MNRA
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