Suchergebnisse

Two groups of subjects solved the same set of 13 troubleshooting and repair problems in seven solid-state-circuit modules which contained as many as five stages each. Both groups used the same hand tools and test equipment. One group was composed of 41 conventionally trained Air Force 5-and 7-level technicians who normally maintain such equipment as part of their Jobs. The technicians used the same troubleshooting techniques they ordinarily used on their jobs, and they were provided with a performance aid resembling an Air Force technical order. The other group was composed of 20 high-school students with no prior training or experience in electronics. Their training for this study consisted of a 12-hour course in the use of hand tools and test equipment and in the use of the proceduralized troubleshooting aid evaluated in this study. The aid indicated which check to make based upon the outcome of previous checks. Using the proceduralized troubleshooting aid, the high-school students took significantly less troubleshooting time than did the experienced technicians using normal techniques; however, the technicians required significantly less repair time and made significantly fewer errors than did the students. These differences may be accounted for in part by differences in the tasks and scoring methods for the two groups, and there were no differences between the two groups on a number of other measures. However, the difference in training time and, therefore, cost of training between the two groups was so great as to suggest the possibility that job-relevant training and proceduralization of the task can introduce substantial savings, even after the cost of developing the special performance aids required by proceduralized troubleshooting is subtracted.

The volume evaluates the ecological role of protozoa in the sea. The major points of discussion are the role of protozoa in the microbial food web, in the cycling of carbon and nitrogen and the extent to which this web acts as a link or sink to metazoa in the water column. The following topics are covered: Taxonomy - Methods - Pollution - Symbiosis - Autecology - Trophic Behav- iour - Community Grazing - Energetics and Production - Marine "Snow" and "Fluff" - Mineral Flux - Nutrient Cycling - Modelling

OBJECTIVE--To emphasise that tetanus still occurs in the United Kingdom, particularly in elderly people-as illustrated by two case reports-and to examine the state of tetanus immunity in elderly people. METHODS--111 elderly people (over 65 years) were studied: 43 males, mean age 77.7 years, range 67-94; 68 females, mean age 81.3 years, range 67-95. They were either attending the accident service or were hospital inpatients. An attempt was made to obtain an immunisation history and antitetanus antibody titres were measured. RESULTS--Immunisation history was uncertain and unreliable. Measurement of antibody titres showed that they were inadequate to ensure protection in 50% of those studied. Low levels were particularly prevalent in the over 80 age group and in females. Questioning about military service confirmed that this had predominantly involved males. CONCLUSIONS--Elderly people are at risk of contracting tetanus and should be targeted for community immunisation. Extra precautions in the form of passive immunisation with human anti-tetanus immunoglobulin should be used in this age group in addition to the usual wound management measures when the elderly sustain tetanus prone injuries.