A study of the effects of ground cover on overwintering slug populations and effect of coulter design on slug incidence in direct drilling : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Massey University

A two stage study involving the effect of vegetation cover on overwintering slug populations, and the effect of coulter design on slug incidence and damage in a direct drilled cereal was carried out during the 1980/81 growring season. The first stage of the study showed that ground cover affected slug activity on the soil surface, but only in the most adverse environment did any actual decrease in slug populations occur. Differences occurred in the effectiveness of the trapping techniques depending on the density of the ground cover. Pitfall traps appeared to be more effective in dense ground covers, while brick or shelter traps appeared to be more effective in low density ground covers and especially with bare ground. Rainfall, soil temperature and soil moisture were measured and it appeared that slug numbers recorded in the traps were correlated to different environmental parameters depending on the ground cover. In dense covers the slug number recorded was correlated to temperature, in medium density ground covers the numbers had a slight correlation to soil moisture, and in low density ground covers they were correlated to rainfall. The second stage of the study involved two dates of drilling, using three coulter types (triple disc, hoe, chisel coulter) and measuring slug numbers occurring in the seed grooves and slug damage to seeds and seedlings. It was found that coulter design had no effect on slug ingression into the seed groove, or on slug damage to the direct drilled crop. There was however a strong correlation between slug numbers in the seed groove and seed and seedling damage (r=0.78, r=0.93 respectively). Pre drilling conditions affected the number of slugs entering the seed grooves (the denser the vegetation the greater the slug number occurring in the seed groove), and slug damage to the seedlings. Moisture levels also affected the number of slugs entering the seed grooves and seed and seedling damage by slugs. Moister conditions produced the greater number of slugs in the seed grooves and the highest seed and seedling damage

The Wilson Loop in Yang-Mills Theory in the General Axial Gauge

We test the unified-gauge formalism by computing a Wilson loop in Yang-Mills theory to one-loop order. The unified-gauge formalism is characterized by the abritrary, but fixed, four-vector $N_\mu$, which collectively represents the light-cone gauge $(N^2 = 0)$, the temporal gauge $(N^2 > 0)$, the pure axial gauge $(N^2 < 0)$ and the planar gauge $(N^2 < 0)$. A novel feature of the calculation is the use of distinct sets of vectors, $\{ n_{\mu}, n_{\mu}^{\ast} \}$ and $\{N_{\mu}, N_{\mu}^{\ast}\}$, for the path and for the gauge-fixing constraint, respectively. The answer for the Wilson loop is independent of $N_{\mu}$, and agrees numerically with the result obtained in the Feymman gauge.Comment: 12 pages, 2 figure

Three-dimensional coating and rimming flow : a ring of fluid on a rotating horizontal cylinder

The steady three-dimensional flow of a thin, slowly varying ring of Newtonian fluid on either the outside or the inside of a uniformly rotating large horizontal cylinder is investigated. Specifically, we study “full-ring” solutions, corresponding to a ring of continuous, finite and non-zero thickness that extends all the way around the cylinder. In particular, it is found that there is a critical solution corresponding to either a critical load above which no full-ring solution exists (if the rotation speed is prescribed) or a critical rotation speed below which no full-ring solution exists (if the load is prescribed). We describe the behaviour of the critical solution and, in particular, show that the critical flux, the critical load, the critical semi-width and the critical ring profile are all increasing functions of the rotation speed. In the limit of small rotation speed, the critical flux is small and the critical ring is narrow and thin, leading to a small critical load. In the limit of large rotation speed, the critical flux is large and the critical ring is wide on the upper half of the cylinder and thick on the lower half of the cylinder, leading to a large critical load. We also describe the behaviour of the non-critical full-ring solution, and, in particular, show that the semi-width and the ring profile are increasing functions of the load but, in general, non-monotonic functions of the rotation speed. In the limit of large rotation speed, the ring approaches a limiting non-uniform shape, whereas in the limit of small load, the ring is narrow and thin with a uniform parabolic profile. Finally, we show that, while for most values of the rotation speed and the load the azimuthal velocity is in the same direction as the rotation of the cylinder, there is a region of parameter space close to the critical solution for sufficiently small rotation speed in which backflow occurs in a small region on the upward-moving side of the cylinder

Pay, Performance, and Participation

Our chapter identifies key dimensions on which organizations make employee compensation decisions and examines the emerging research evidence on the consequences of such decisions for attitudes, behaviors, and organization performance. We provide some general suggestions that may prove helpful in future research. First, there is increased recognition that pay decisions take place in the context of implicit or explicit contracts between employees and specific organizations. As a result, we encourage researchers to continue to give greater attention to the role of organization differences in compensation. Second, because pay is multidimensional, attention should not be restricted to organization differences in pay level. Organization differences in benefits, structure, and means of recognizing individual employees contributions also warrant attention. As an example of how the focus can be expanded, we provide new empirical evidence on organization differences in the market sensitivity of pay structures. Third, we note that the success of pay programs depends not only on decisions about pay per se, but also the process used in making communicating, and administering such decisions. More broadly, the influence of contextual factors, such as the nature of other employee relations practices (e.g., staffmg, development, employment security), needs to be considered to a greater extent in compensation research. In addition to these broad suggestions, we provide specific ideas on future research directions throughout the chapter

Increased Lower Limb Spasticity but Not Strength or Function Following a Single-Dose Serotonin Reuptake Inhibitor in Chronic Stroke

Objective: To investigate the effects of single doses of a selective serotonin reuptake inhibitor (SSRI) on lower limb voluntary and reflex function in individuals with chronic stroke. Design: Double-blind, randomized, placebo-controlled crossover trial. Setting: Outpatient research setting. Participants: Individuals (N=10; 7 men; mean age ± SD, 57±10y) with poststroke hemiplegia of \u3e1 year duration who completed all assessments. Interventions: Patients were assessed before and 5 hours after single-dose, overencapsulated 10-mg doses of escitalopram (SSRI) or placebo, with 1 week between conditions. Main Outcome Measures: Primary assessments included maximal ankle and knee isometric strength, and velocity-dependent (30°/s–120°/s) plantarflexor stretch reflexes under passive conditions, and separately during and after 3 superimposed maximal volitional drive to simulate conditions of increased serotonin release. Secondary measures included clinical measures of lower limb coordination and locomotion. Results: SSRI administration significantly increased stretch reflex torques at higher stretch velocities (eg, 90°/s; P=.03), with reflexes at lower velocities enhanced by superimposed voluntary drive (P=.02). No significant improvements were seen in volitional peak torques or in clinical measures of lower limb function (lowest P=.10). Conclusions: Increases in spasticity but not strength or lower limb function were observed with single-dose SSRI administration in individuals with chronic stroke. Further studies should evaluate whether repeated dosing of SSRIs, or as combined with specific interventions, is required to elicit significant benefit of these agents on lower limb function poststroke