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Background--Engaging older persons in consideration of use of life-sustaining measures, such as cardiopulmonary resuscitation, tube feeding, and urgent intubation, is widely recommended, yet uncommon. Methods.--We studied the short-term impact of a physician-initiated discussion, geared toward guiding informed decision-making, with 20 frail elderly homebound patients. A battery of psychologic rating scales was administered in a pre-post design. Eighteen subjects completed the protocol. Fifteen of the mentally capable surviving subjects were reinterviewed 18 months following the initial discussion to evaluate durability of their decisions. Results.--Most welcomed the discussion and clear choices regarding future care usually emerged. Depression rating scales decreased slightly for the entire sample. For the subgroup having relatively internal locus of control, there was an increase in life satisfaction scores. No patient demonstrated signs of emotional trauma consequent to the discussion. On follow-up, several patients were indecisive about their choices. Conclusion.--Involvement of these patients in decision-making appeared to have no adverse effects, and, for some, it was therapeutic, possibly through enhancement of personal control. Durability of their decisions was not a consistent finding, however. (Arch Intern Med. 1992;152:2317-2320)

It has been shown that Drosophila melanogasterfly to the source of an attractive scent by making a series of highly stereotyped responses to olfactory and visual stimuli (Kellogg, Frizel, and Wright, 1962). The comparable processes by which Aedes aegyptiare guided to a warm-blooded host have now been studied and are the subject of this paper.

In a previous communication (Kellogg and Wright, 1962a), we have drawn attention to the role of warm wet convection currents in bringing about the alightment of Aedes aegyptiafter they have been stimulated to fly by human breath. In some of those experiments, copper bars were warmed at one end and cooled at the other and covered with dampened cloth, and the number of mosquitoes touching or alighting at various points along their length was counted. The results showed that the warm wet end was highly attractive.

The upwind guidance of flying insects was considered in a previous paper (Wright, 1958) where a homing mechanism was suggested that did not require visual contact with the ground. The response of Drosophilato attractive scents presented in various ways has now been studied. The results show that visual contact with the ground is in fact essential, and other factors of the guidance system have been clarified.

It has been suggested (Wright, 1958) that attractants or repellents for insects which normally fly to their destination should be tested against insects that are in flight during the tests. Moreover, the conditions of the flight should be as nearly natural as possible. This requires that the observation chamber should be large (to minimize wall effects), the illumination should be controllable, and the air movement and the odorous or other signals should be presented in a natural way. Finally, the movements of the insects should be recorded in three dimensions, and in as much detail as possible.

AbstractA machine is described which generates a standard, mosquito-attracting ?target? to which controlled additions of various volatile chemicals can be made and the amount needed to repel the insects thereby measured in micromoles per liter of air. The apparatus can be used with both solids and liquids as well as with blends or mixtures. While principally intended for testing mosquito repellents, it can probably be adapted for use with other biting insects and ticks.

AbstractThe spontaneous activation of Aedes aegypti, and their responses to external stimuli (especially changes in temperature, humidity and carbon dioxide concentration) have been analyzed in a way that allows the controlling neural mechanisms to be inferred. In general, the flying insect turns back on leaving a favorable air stream, but does not turn on entering one. The normal attack program reduces to four basic steps: a general search initiated by a small rise in the CO2level, no turnwhen the insect enters the "host stream" (i.e., the convective or other air current whose temperature and/or relative humidity has been modified by the host), an induced turnon leaving the host stream, and a visual landing. Repellents resemble CO2in activating previously resting mosquitoes. If, however, the host stream contains a repellent vapor, the insect is made to turn on enteringthe host stream and is prevented from turningon leaving it. Thus the repellent vapor reverses the normal response to the host stream in two ways that are vital to success in locating a warm-blooded host. It also tends to inhibit probing. The antennal setae through which the various environmental influences are perceived can be inferred from a quantitative consideration of the responses.

AbstractThe paper describes an observation chamber and air-conditioning system designed for studying the responses of flying insects at the boundary between two microclimates. Two vertical air streams each fill one half of the rectangular observation chamber. Turbulence is carefully removed so as to maintain a sharp boundary between the streams. Each stream is separately conditioned by passage through heat exchangers and plastic sponges impregnated with substances to be vapourized. Responses of flying insects are studied both photographically and by counting rates of turning at the boundary.

• The relationships of familial hypertension and height, weight, and blood pressure (BP) were studied in two adolescent populations. Subjects having hypertensive first-degree relatives were matched to control subjects without such a family history. The group with familial hypertension demonstrated a slightly higher average BP but also had a greater mean body weight and ponderal index than the control group. After controlling for weight, male but not female subjects with a family history of hypertension had a greater prevalence of elevated BP and higher average pressures than controls. The factors of above-average weight and familial hypertension appear to interact so as to produce an excessive prevalence of elevated BP. These trends suggest that teenagers with hypertensive first-degree relatives constitute a special risk group that should be closely monitored.(Am J Dis Child 1981;135:1047-1049)