The degree to which a person perceives that the outcomes of the situations they experience are under their personal control is a psychological variable known as Locus of Control (LOC). An Aviation Safety LOC Scale has been developed to specifically address the construct of internal and external LOC among pilots. An external LOC has been associated with resignation and an internal LOC with less involvement in hazardous aviation events. The aim of this study was to investigate whether there was a significant difference between the internal and external LOC scores in Indian aviators and to delineate whether LOC was correlated with any demographic variables. A group of 101 male pilots were administered the Aviation Safety LOC scale. Separate internal, external and combined scores were generated from the item responses and were statistically analysed. Results indicated that there was a significantly higher internal than external LOC score in aviators. These scores also had a significant negative correlation. Civil pilots had higher internal LOC scores and combined LOC scores than the military pilots. It was also found that transport pilots had the highest internal and combined LOC scores, the fighter pilots were the next highest and the helicopter pilots were the least. LOC was not associated with demographic variables such as age and flying hours. An external LOC was negatively correlated with years of education and service. Medically fit pilots had a higher internal LOC score than the unfit pilots. In Indian aviators, LOC appears to be a robust attribute related to type of flying, aircraft stream, education, service and medical fitness.
The calcium dependency of hyperosmolality stimulation of atrial natriuretic peptide (ANP) secretion was determined using isolated superfused nonbeating rat left atrium. Increasing osmolality by 65, 85, and 100 mosmol/kgH2O by superfusion with sucrose produced a peak rise in ANP secretion of 1.8-, 2.0-, and 2.7-fold. To determine whether calcium influx played a role in osmolality (osm)-stimulated ANP secretion, atria were superfused with 2 mM lanthanum, a calcium antagonist. Lanthanum inhibited by 85% the response to a 100 mosmol/kgH2O increase in osm. The voltage-dependent calcium channel blocker isradipine had no effect on osm-stimulated ANP secretion, suggesting that calcium influx via voltage-dependent calcium channels was not playing a significant role. Likewise, depleting sarcoplasmic reticulum calcium with 1 microM ryanodine did not block the response to osm, suggesting that calcium influx was not adequate to induce consequential release of calcium from the sarcoplasmic reticulum. To determine whether calcium influx was via Na(+)-Ca2+ exchange, we determined the sodium dependency of osm-stimulated ANP secretion. Replacement of sodium with lithium or choline blocked the secretory response to 100 mosmol/kgH2O. We conclude that osm-stimulated ANP secretion is calcium and sodium dependent. Calcium influx via Na(+)-Ca2+ exchange is highly implicated as the mechanism of cellular calcium entry.
Psychological factors contribute significantly to the pathogenesis of medical illnesses, affect their course and may be a target for effective intervention. Emotional and perceptual factors have been implicated in the maintenance of illness behaviour in both the general and aircrew populations. In aircrew it may influence not only the duration and course of illness but also return back to flying. The aim of this study was to determine whether there is a statistically higher incidence of certain personality characteristics in three different groups of referred military aircrew. One hundred and fifteen aircrew were studied in three groups; non clinical (NC), musculoskeletal disabilities (MD) group and other medical disabilities (OMD) group using the Rorschach test indices. All underwent a clinical interview and were administered the Rorschach test individually with no testing of limits by one of two trained psychologists. Responses were scored following Rapaport’s method in terms of location, determinants and content. Results were then tabulated according to the presence or absence of 18 personality characteristics derived from the Rorschach indices which was then statistically analysed using the χ2 test. Results indicated that all three groups showed deviations from optimal perceptual generalization and the NC group also had difficulty in differentiation, deficiencies in affectional needs and emotional over reactivity. A significant number of aircrew in the clinical groups showed anxiety and somatisation. A significantly high number of aircrew in all three groups showed non optimal emotional responsivity and reactivity. Different patterns of emotional and perceptual responses are observed in referred clinical and non clinical aircrew groups. The implications for interventions and remedies are discussed.
