The effects of soil properties and applied water on the leaching of atrazine, simazine, diuron and DCPA in soil columns

Today, there is an increasing demand for information regarding the disappearance of herbicides from soils. Such information is important from at least two standpoints. First, it is essential that a soil-applied herbicide remain in an active state long enough to do the job for which it was intended. Second, its phytotoxicity should become dissipated rapidly enough so that sensitive crops which follow will not be injured. Not only is it possible for frequently applied herbicides to build up to toxic levels even for tolerant crop plants, but often residues from spring-applied herbicides remain in the soil to affect sensitive fall-seeded plants. Little is known at the present time about what happens to herbicides under a variety of edaphic and climatic conditions. Even when herbicides are applied directly to plants, a substantial amount eventually reaches the soil. The problem of persistence of herbicides in soils is one which faces both farmers and research workers. Disappearance of herbicides from soils is a complex process which is affected by several interacting variables. These variables include type and rate of application of the herbicide, physical and chemical soil properties, amount of leaching by rainfall, microbiological activity, chemical decomposition, volatilization, photo-decom-position, and plant uptake. The persistence of a herbicide in a given situation is governed by the prevailing combination of these variables. This study deals with leaching which is one of the most important factors affecting disappearance of herbicides from soils. In humid agricultural regions particularly, leaching is a major factor influencing the success or failure of preemergence herbicides. The purpose of this study was to determine the effects of three rates of applied water on movement of four herbicides in columns of four soils

Baroclinic geostrophic adjustment in a rotating circular basin

Baroclinic geostrophic adjustment in a rotating circular basin is investigated in a laboratory study. The adjustment process consists of a linear phase before advective and dissipative effects dominate the response for longer time. This work describes in detail the hydrodynamics and energetics of the linear phase of the adjustment process of a two-layer fluid from an initial step height discontinuity in the density interface DeltaH to a final response consisting of both geostrophic and fluctuating components. For a forcing lengthscale r(f) equal to the basin radius R-0, the geostrophic component takes the form of a basin-scale double gyre while the fluctuating component is composed of baroclinic Kelvin and Poincare waves. The Burger number S=R/r(f) (R is the baroclinic Rossby radius of deformation) and the dimensionless forcing amplitude epsilon = DeltaH/H-1 (H-1 is the upper-layer depth) characterize the response of the adjustment process. In particular, comparisons between analytical solutions and laboratory measurements indicate that for time tau: 1 < tau < S-1 (tau is time scaled by the inertial period 2pi/f), the basin-scale double gyre is established, followed by a period where the double gyre is sustained, given by S-1 < tau < 2epsilon(-1) for a moderate forcing and S-1 < tau < tau(D) for a weak forcing (tau(D) is the dimensionless dissipation timescale due to Ekman damping). The analytical solution is used to calculate the energetics of the baroclinic geostrophic adjustment. The results are found to compare well with previous studies with partitioning of energy between the geostrophic and fluctuating components exhibiting a strong dependence on S. Finally, the outcomes of this study are considered in terms of their application to lakes influenced by the rotation of the Earth

Virginia Practice Series: Jury Instructions

Virginia Practice Series-Jury Instructions is a continuation and update of previous editions, which won widespread approval among the bench and bar for almost 40 years. As in the past, this book is primarily confined to the most common areas of jury trial work, torts and criminal law. Where possible, the language of the instructions is taken directly from reported cases or case records. Where this is not possible, we have set out instructions that should meet both the general rules regarding the form of instructions and the specific substantive legal rules. In the latter cases, close attention has been paid to statements that the Supreme Court and the Court of Appeals have made indicating how a proffered instruction might be improved. The suggested instructions try to balance specificity with flexibility, so that they can readily be adapted to the precise circumstances of each case. Nearly every suggested instruction is followed by a comment that sets forth the legal authority underlying the instruction and, in some cases, an extensive discussion of the law. This publication will be recompiled on an annual basis. Any changes or expansions of the law will be included in amended or additional instructions, comments, and citations. We look forward to carrying on a tradition that, since 1964, has been of great assistance to the bench and bar of Virginia

When Racists and Radicals Meet

In order to stimulate scholarly discussion, this Essay presents an empirical account of the Greensboro incident from the perspective of those who participated in the episode and in the resulting civil rights trial. The Essay traces the circumstances leading to the violence and reviews the resultant litigation with special attention given to the role of the trial judge in politically volatile cases. The candid reflections offered by the trial judge and other participants allow the reader to examine both the event and the litigation, not merely in the abstract, but as implemented by flesh-andblood lawyers, litigants, and judges.