Multiloop pilot/vehicle analysis is applied to the problem of determining crossfeed techniques which may be employed by pilots in minimizing the effects of vehicle cross coupling. As used here, cross coupling refers to unwanted vehicle motion which occurs in one control axis or loop as the result of pilot control actuation in another control axis or loop. The minimization or elimination of such cross coupling can contribute significantly to the 'workload' associated with tasks like nap-of-the-earth helicopter flight. In contrast, situations arise in which pilot's may use vehicle cross coupling to improve performance by coordinating two control actuations in the control of a single response variable. A crossfeed model is developed based upon simple control system design principles and configured in a manner amenable to pilot pursuit or precognitive control activity. A handling qualities theory developed to analyze single loop tasks is applied to the multiloop problem. The crossfeed model is applied to five different vehicles/configurations ranging from helicopters to fighter aircraft. Results indicate relatively simple crossfeed commands can significantly reduce cross coupling and, in some improve handling qualities as predicted by the single loop theory.

Intraarterial digital subtraction angiography (IA-DSA) was performed in 80 pediatric patients. Forty-four underwent arterial injections with digital filming techniques. Of the 130 injections, DSA imaging was good or excellent in 121, often allowing resolution of vessels 1 mm in size. Thirty-six of the 80 patients underwent cardiac evaluation with intra-cardiac injections. Improved contrast resolution with IA-DSA allowed the use of smaller catheters (3–4 F) and smaller amounts of contrast material. Immediate availability of subtracted images (no film processing delay) resulted in shorter total procedure time. Outpatient studies are possible. IA-DSA provides several notable advantages for the pediatric patient.

The relative importance of the form and toughness of the seaweed thallus has been investigated in rela t ion to defence against grazing Iittorine snails. The narrow, buoyant frond of Enteromorpha intestinalis Link is more difficult to manipulate and ingest by Littorina Uttorea (L.) than the broader lamina of Viva lactuca L. Consequently, Ulva is grazed preferentially in choice experiments. Presentation of the algae to feeding winkles as small, uniform fragments excised from intact fronds reverses this preference. Lamina "toughness" is assessed for a variety of common macroalgae in terms of puncture strength and resistance to abrasion using respectively, a Shore durometer and an abrasive wheel. Toughness rankings based on these two distinct criteria differ markedly. The foliose species, whilst readily penetrated by the durometer needle, appear remarkably resistant to damage by abrasion. Ascophyllum nodosum (L.) Le Jol and Mastocarpus stetlatus (Stackh.) Guiry (= Gigartina siellata) proved to be 'tough' whatever the nature of the test force applied. It is postulated that radula structure may interact with frond toughness to influence the feeding preferences of Iittorine snails.

A fermentor system with an external filtration loop has been developed to control the growth and sporulation of yeast in a single vessel. Excess growth medium, instead of being removed by centrifugation, is removed by filtration and replaced with acetate sporulation medium. The technique did give 80% sporulation after 20 hr, greatly improving the rate and degree of synchrony of sporulation and it also eliminated the contamination hazard of the conventional harvest technique, centrifugation, and resuspension of vegetative cells in sporulation medium. Furthermore it permits proper control of the environmental conditions throughout the growth, exchange, and sporulation phase. In this technique 100% recycle of biomass is achieved without any packing of the cells on the filter. This technique has wide application in the study of industrial fermentation that involves microbial differentiation such as the production of ergot alkaloids, bacitracin, and cephalosporin.

A new design for an emergency transthoracic pacing wire ensures electrode stability by engaging the myocardium rather than the endocardium. Lessened are the hazards of myocardial puncture, intraventricular thrombus, and endocarditis. Pacing studies have shown the system is safe, readily deployed, and of low threshold.