Deep plowing reduced uptake of Sr by four irrigated crops on Pullman silty clay loam at Bushland, Texas. Uptake was further reduced when Na2CO3 was plowed under with the Sr. The relative concentrations of Sr in mature soybean (Glycine max), sugar beet (Beta vulgaris), sudangrass (Sorghum sudanense), and cabbage (Brassica oleracea var capitata) plants grown with Sr applied in different treatments were: rotary tilled 20 cm deep, 100; plowed 90 cm deep, 25-50; plowed 90 cm deep with 22,400 kg/ha (10 tons/acre) of Na2CO3, 3-7. In the plowing treatments, 90% of both the Sr and the Na2CO3 were banded in the furrow deeper than 75 cm. Crop yields were increased by deep plowing and were affected very little by the application of Na2CO3. This experiment demonstrates that a toxic chemical can be plowed under deeply with radioactive contamination to reduce the uptake of the radioactive material with little effect on yield from the chemical. Additional

About 86 percent of the erosion in the dryland cropping areas of the Pacific Northwest occurs during low intensity rainfall on frozen soil, snow melt on frozen soil, or rain and snowmelt on frozen soil (Zuzel et al. 1982). Soil loss is greatest from the approximately 4.5 million acres (Smiley 1991, McCool et al. 1993) that are planted to winter wheat following summer fallow. Soil loss from the more erodible of these fields will range from 10 to 150 t yr.

To the Editor: I write to Neurology and the American Academy of Neurology (AAN) not regarding the content of the special article entitled “Reassessment: vagus nerve stimulation for epilepsy,”1 but regarding the principles underlying critical reviews. Given the scientific background of our profession, I would assume that a subcommittee titled “Therapeutics and Technology Assessment” would have a mandate to critique objectively. Can Drs. Fisher and Handforth1 be objective? “Disclosure: Both authors have received speaker’s bureau support from Cyberonics … Dr. Handforth has received research support from Cyberonics and also served as the lead author in the E05 study of VNS … .”1 It is unrealistic that some degree of bias, perhaps even considerable bias, will not color their words. Why did the AAN choose …

A sound assessment of hydrologic and erosional responses in wildland and agricultural ecosystems to rainfallrequires that rainfall simulators mimic natural rainfall. The accuracy and usefulness of the assessment improves withincreased similarity between natural and simulated rainfall. Some characteristics of natural rainfall important to rainfallsimulation include rainfall energy, intensity, distribution, drop size distribution, time or season of application, and plotsize. Our purpose for constructing a new rainfall simulator was to improve an old design with current technology. Thisequipment is especially needed for research in regions with low energy rainfall and convectional storms are not theprimary source of excess rainfall and subsequent erosion. We developed a new rainfall simulator to simulate low energyrainfall under a wide range of ambient weather conditions. The simulator consists of four structures. Each structuresimulates rainfall onto a 1.5 m wide 9.1 m long plot, and consists of a frame for structural support and wind screening,three rotating disk-single nozzle modules, and control systems. The nozzle modules produce rainfall at five discreteintensities; 4.5, 9.0, 13.4, 17.9, and 35.8 mm/h. At the control center, water pressure at each nozzle is monitored andcontrolled to insure consistent rainfall over all treatments. Data loggers record water and air temperature in eachstructure during rainfall simulations. We tested uniformity of rainfall distribution and rainfall intensity. The coefficient ofapplication uniformity for rainfall distribution within each structure is greater than 76, and rainfall intensity does notvary significantly ( 1 standard deviation) between structures. For our purposes, we developed this simulator for theevaluation of residue management, tillage methods, and farming systems. We used the simulator in subfreezing weather toevaluate residue management practices and concluded that the simulator is operable for data collection during allseasons and temperatures ranging from 5C to 40C. Rainfall simulation continues to be an important tool in efforts tounderstand how wildland ecosystems function and how agricultural practices might be improved. This rainfall simulatoris an appropriate tool for hydrologic and erosion research in low energy rainfall regions.

Field tests were conducted to evaluate header grain loss for a combine equipped with a 3.7 m (12 ft) wide Shelbourne Reynolds stripper-header harvesting wheat. Eight tests were conducted over two years in the Columbia Plateau and Northern Great Plains. Hard red spring and winter wheat were harvested near Sidney, Montana, and soft white wheat was harvested near Pendleton and Moro, Oregon. Combine speed, stripper rotor speed, and stripper hood position were evaluated at these locations where grain yield ranged from 2 000 to 6 200 kg/ha (30 to 92 bu/acre). Losses ranged from 50 to over 500 kg/ha (0.74 to over 7.4 bu/acre). Header loss decreased with increased combine speed and decreased hood clearance, but stripper rotor speed had little influence on header loss. A stripper-header combine traveling over 7 km/h (4.3 mile/h) had comparable header loss to combines with cutter-bar headers traveling at 1.3 to 4.4 km/h (0. 8 to 2.7 mile/h).

Hydraulic-powered soil samplers speed and simplify the collection of soil cores and plant root samples. Unfortunately, the vehicle carrying a sampler often damages a large area of the crop surrounding a sampling site and compacts the soil surface. The extent of such damage often prevents the use of powdered samplers. An attachment linking a Giddings1 hydraulic probe to a knuckle boom mounted on a 3-t truck permitted removing soil cores from small field plots with virtually no damage to the crop or soil at the sample site (except for foot traffic). The objectives of this note are to describe and illustrate the attachment and present some examples of rapid, easy collection of soil cores that it provided. The hydraulic probe, when mounted at the end of a knuckle boom, was not restricted in any of its operations.

Two new prototype conservation seeders and an end-wheel seeder were evaluated in the Pacific Northwest dryland production area for seeding edible green peas. Field tests were conducted in 1989 and 1990 on plots with no tillage or fall chisel plowing plus secondary field cultivations prior to seeding. A strip-till seeder and cross-slot seeder showed good potential for spring seeding peas into chisel plowed and untilled wheat stubble. The end-wheel seeder performed well in tilled plots. There were no significant differences in the amount of soil water lost between seeding and emergence for the three seeders. Regardless of the seeder or prior tillage, when seeds were placed in contact with soil that had between 50 and 150 kPa (0.5 and 1.5 bars) water tension, over 85% of the seeds emerged and established plants.

ABSTRACT The expert system, PLANTING, has been designed to systematically develop specifications for soil-engaging components on conservation planters, drills and seeders. It is intended for use by farm advisors and others v^hen consulting with a farmer on adoption of conservation-tillage crop production. PLANTING is loaded with a soil and weather condition data base, specifically for the user's area. Warning messages are given to the user if intended cropping practices may pro-duce excessive soil erosion, machine incompatibilities and other irregularities. A report is printed which con-tains recommended planting machine components for each of seven machine functions. Required components may be added to existing machines for conservation planting. The specifications are matched to available planting machines as a guide to machine selection.

THIS guideline contains descriptions of machines used for planting in conservation-tillage conditions and of soil-engaging components for those machines. The functions of available components are discussed relative to soil and crop residue conditions that may be encountered with conservation tillage. The guideline aids in determining planting machine specifications by identifying components that will work best under specific anticipated conditions. The user can then match those specifications with available commercial machines or modify existing machines by adding the desired components.

Standing wheat stubble decreased seed-level soil temperature and mid-canopy photosynthetically-active radiation compared with burned plots. Plants within standing stubble had reduced main-stem leaf development, drastically reduced tillering and above-ground dry weights at late tillering, and had shorter stems at harvest. Because growing conditions from anthesis to maturity were highly favorable, depressed plant development and growth caused by standing stubble decreased grain and straw yield only slightly.

The normal human audiogenic startle reflex is defined from a review of the literature, substantiated by a current investigation of normal subjects, and clarified pathophysiologically by a discussion of animal experimentation. The basic information is used to evaluate critically a variety of syndromes loosely termed 'startle' in the past. A new classification of startle syndromes is proposed.

The typical electrophysiological correlates of myoclonus in Alzheimer's disease are similar to those of cortical reflex myoclonus, with a focal, contralateral negativity in the EEG preceding the myoclonic jerk. One difference from cortical reflex myoclonus is that the duration of the negativity is longer and its onset before the jerk earlier. The features differ from those described for subacute spongiform encephalopathy and should be helpful for differential diagnosis. The electrophysiological correlate of minopolymyoclonus that can be seen in Alzheimer's disease and in other pathological states is a bifrontal negativity in the EEG that precedes the myoclonic jerk. This new type of electrophysiological correlate of myoclonus may reflect activity of a subcortical generator.

A group of patients with myoclonus is described whose jerks are preceded by a bilaterally synchronous, frontocentrally predominant, negative cerebral potential in the EEG. This potential may be a slow wave with variable timing in relation to EMG bursts, and in this circumstance the muscle jerks are usually small amplitude and multifocal ("minipolymyoclonus"). The cerebral negativity can also be shorter in duration and time-locked to limb jerks, which are larger in amplitude and more widespread. We propose that the physiology of this distinct form of myoclonus is similar to that of primary generalised epilepsy.