Evaluation of Nitrogen and Phosphorus Enrichment Using In Situ Enclosure Bags with Temporal Indigenous Phytoplankton Populations

An in situ experimental procedure and protocol was developed to evaluate nitrate and phosphate enrichment using isolated indigenous phytoplankton assemblages during different seasons. Results of the comparison of the parameters-temperature, pH, alkalinity, conductivity, and dissolved oxygen between the open water and enclosed systems indicated that there was no significant influence of the physicochemical factors on the isolated biological processes. Growth responses were measured by turbidity, biomass and chlorophyll-a, the most sensitive being chlorophyll-a. Additions of nitrate and phosphate were added in known concentrations and in different magnitudes of concentration based upon ambient conditions and ratio. During the fall, phosphorus influenced phytoplankton growth, whereas in the spring both nutrients effect growth response equally, and in the summer nitrate had the greatest influence. Based upon the results of these experiments a sampling regime for physicochemical parameters and growth response is recommended

Systematic Errors in Stereo PIV When Imaging through a Glass Window

This document assesses the magnitude of velocity measurement errors that may arise when performing stereo particle image velocimetry (PIV) with cameras viewing through thick, refractive window and where the calibration is performed in one plane only. The effect of the window is to introduce a refractive error that increases with window thickness and the camera angle of incidence. The calibration should be performed while viewing through the test section window, otherwise a potentially significant error may be introduced that affects each velocity component differently. However, even when the calibration is performed correctly, another error may arise during the stereo reconstruction if the perspective angle determined for each camera does not account for the displacement of the light rays as they refract through the thick window. Care should be exercised when applying in a single-plane calibration since certain implicit assumptions may in fact require conditions that are extremely difficult to meet in a practical laboratory environment. It is suggested that the effort expended to ensure this accuracy may be better expended in performing a more lengthy volumetric calibration procedure, which does not rely upon the assumptions implicit in the single plane method and avoids the need for the perspective angle to be calculated

Security of Tenure and Land Registration in Africa: Literature Review and Synthesis

In 1984, the Land Tenure Center embarked on a project to evaluate the experiences with land registration and tenure reform in Africa. The goal was to determine is African states been able to use tenure reform and land registration to provide greater security of tenure than was available through customary tenure systems. Donor agencies focused attention on the creation of individual freehold title, emphasizing the heightened security of holding, marketability, and access to credit under such tenure. National governments, on the other hand, were more concerned to see that land was used productively rather than merely accumulated for purposes of prestige or inheritance or as a hedge against inflation, and for this reason have tended to favor granting more circumscribed rights, such as leaseholds or rights of occupancy. This literature review and synthesis was prepared as part of an effort to increase very substantially our knowledge, especially on a quantitative level, of tenure and development relationships in Africa. The literature review is an attempt to gather in one place data about the diverse efforts at land registration and to describe briefly for each country the various registration programs that have taken place (if any), why they were undertaken, and what subsequent studies of these programs have found. Among other things, it will be seen that the intended benefits, and beneficiaries, of land registration have changed over the century or so since the first systems were put in place. In addition to these variations over time, there are also differences among Anglophone, Francophone, and Lusophone countries, differences that not only influenced the structure of registration systems established during the colonial era, but also continue to inform the kinds of registration systems adopted today.Land Economics/Use,

What is the Best Soybean Row Width? A U.S. Perspective

What is the best row width for soybeans? That seemingly simple question has been the subject of debate and research for about 80 years - ever since people stopped thinking of soybeans as a hay crop and started considering it a grain crop

Forced Sale Risk: Class, Race, and the Double Discount

What impact does a forced sale have upon a property owner\u27s wealth? And do certain characteristics of a property owner such as whether they are rich or poor or whether they are black or white, tend to affect the price yielded at a forced sale? This Article addresses arguments made by some courts and legal scholars who have claimed that certain types of forced sales result in wealth maximizing, economic efficiencies. The Article addresses such economic arguments by returning to first principles and reviewing the distinction between sales conducted under fair market value conditions and sales conducted under forced sale conditions. This analysis makes it clear that forced sales of real or personal property are conducted under conditions that are rarely likely to yield market value prices. In addition, the Article addresses the fact that judges and legal scholars have utilized a flawed economic analysis of forced sales in cases that often involve property that is owned by low- to middle-class property owners in part because those who are wealthier own their property under more stable ownership structures or utilize private ordering to avoid the chance that a court might order a forced sale under the default rules of certain common ownership structures. The Article also raises the possibility for the first time that the race or ethnicity of a property owner may affect the sales price for property sold at a forced sale, resulting in a double discount, i.e. a discount from market value for the forced sale and a further discount attributable to the race of the property owner. If minorities are more susceptible to forced sales of their property than white property owners or if there does exist a phenomenon in which minorities suffer a double discount upon the sale of their property at a forced sale, then forced sales of minority-owned property could be contributing to persistent and yawning racial wealth gaps

Methods for Comparison of Markov Processes by Stochastic Dominance

A technique is developed for proving existence and obtaining bounds for the concentration of a stationary distribution for a given Markov process on the basis of comparisons, via stochastic dominance, with a different Markov process, having a known stationary distribution

Ultraviolet Broad Absorption Features and the Spectral Energy Distribution of the QSO PG 1351+64

We present a moderate-resolution (~20 km/s) spectrum of the mini broad-absorption-line QSO PG1351+64 between 915-1180 A, obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). Additional spectra at longer wavelengths were also obtained with the HST and ground-based telescopes. Broad absorption is present on the blue wings of CIII 977, Ly-beta, OVI 1032,1038, Ly-alpha, NV 1238,1242, SiIV 1393,1402, and CIV 1548,1450. The absorption profile can be fitted with five components at velocities of ~ -780, -1049, -1629, -1833, and -3054 km/s with respect to the emission-line redshift of z = 0.088. All the absorption components cover a large fraction of the continuum source as well as the broad-line region. The OVI emission feature is very weak, and the OVI/Lyalpha flux ratio is 0.08, one of the lowest among low-redshift active galaxies and QSOs. The UV continuum shows a significant change in slope near 1050 A in the restframe. The steeper continuum shortward of the Lyman limit extrapolates well to the observed weak X-ray flux level. The absorbers' properties are similar to those of high-redshift broad absorption-line QSOs. The derived total column density of the UV absorbers is on the order of 10^21 cm^-2, unlikely to produce significant opacity above 1 keV in the X-ray. Unless there is a separate, high-ionization X-ray absorber, the QSO's weak X-ray flux may be intrinsic. The ionization level of the absorbing components is comparable to that anticipated in the broad-line region, therefore the absorbers may be related to broad-line clouds along the line of sight.Comment: 23 pages, Latex, 5 figure

Algal Growth Potentials and Heavy Metal Concentrations of the Primary Streams to Upper Beaver Lake

Meyer and Green (1984) demonstrated the probable inhibition of algal growth potential by heavy metals in upper Beaver Lake. Upper Beaver Lake receives water from three tributaries. One contains a small reservoir and the combined streams receive sewage input. Collections were made approximately monthly at eight sites for the Algal Assay Bottle Test (AABT) and heavy metal analysis. In general, AABT results indicated that the collections above the sewage lnput were phosphorus limited while those below were nitrogen or combined nitrogen and phosphorus limited. Growth inhibition occurred during summer and early fall at various sites with greater inhibition at the confluence of the streams. No inhibitions occurred, at the site below the sewage input. Heavy metal concentrations had an overall tendency to increase downstream. Values within the small reservoir were 50-100% higher than in the feeder stream. Highest values of Pb were observed below the reservoir. SO4 ,Cl, Mg, Ca, Na and K had high values during low flow in August-ctober. The low values were independent of high flow. Pb followed an independent pattern. Storm event results showed that the Ca maximum was before the hydrographic peak while Fe, Mn, Pb, In, Co, Ni, Cu and Cd attained their maximum just after the peak. Maximum values were 4-10 times background values. Mn, Pb and Fe exceeded EPA recommended standards for drinking water

In-The-Row Subsoiling of Tobacco

Tobacco is probably more adversely affected by soil compaction than, the other crops grown in Kentucky. ThIs Is due to the characteristIcs of the plant and the unusual cultural practIces under which it is grown. Soil compaction increases soil density while reducing pore space and root penetration. The reduced pore space reduces the aeration of the soil, which reduces tobacco growth especially during wet periods. The effects of soil compaction on tobacco are due to both impedance of root growth and lack of aeration