Controlling the uncontrollable: Effects of stress on illusory perceptions of controllability.

Individuals' failure to exercise actual control over an event might be compensated for by trying to bolster a generalized, subjective sense of control. Control might then be sought by undertaking acts the effect of which on the environment is illusory. This observation led to the hypothesis that stress, which undermines persons' sense of control, would engender illusory perceptions of controllability. The hypothesis was tested in 3 experiments that required Ss to choose between 2 gambling forms. Although the 2 forms were essentially identical, 1 was designed to instill an illusion of control. The results showed that highly stressed Ss, compared with those who experienced low stress, preferred gambling forms that heightened perceptions of controllability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Orthophosphate solubility in waters of different ionic composition

Orthophosphate (OP) is a major component of irrigation and nutrient solutions. Since OP precipitates may clog drippers, and deviations from intended OP concentrations may adversely affect plant development and yield, an understanding of the mechanisms controlling OP solubility in solutions of various ionic compositions, is essential.The objectives of this study were (i) to suggest guidelines for permitted OP additions to waters of various ionic compositions, so as to avoid OP crystallization and (ii) to predict the decrease in OP concentration as a function of time in supersaturated solutions.Five freshwater sources, used for irrigation in Israel, and representing extremes of pH and of Ca, HCO₃ and SO₄ concentrations, were tested. Solutions of three different initial OP concentrations (10, 30 and 90 mg Pl^–1) and two pH values were prepared in 21 plastic bottles and kept in a dark room at 27 °C. Solution samples were withdrawn from the bottles at predetermined times, filtered and analysed for pH and total OP, Ca and HCO₃ concentrations.In all the studied waters and for all initial OP levels the OP concentration (C_p) declined with time. The rate of decrease in C_p was proportional to the difference between the observed and equilibrium C_p values, with a specific rate constant for each water.The pH and the Ca²⁺ and HCO ₃ ^– activities in solution were influenced by the initial C_p. The equilibrium C_p in all treatments was found to be controlled by octacalcium phosphate (OCP). Available chemical equilibria models allow to calculate the maximum level of OP that can be added to various waters before OCP precipitates, based on water pH and Ca, HCO₃ and SO ₄ ^2– concentrations.Contribution from the Agricultural Research Organization, The Volcani Center, Bet-Dagan 50250, Israel. No 1340-E, 1994 Series.     

Stress and burnout in Israeli border police.

Despite great interest in police stress, very little research attention focused on border police. The study aimed to map the stressors that effect Israeli border police (MAGAV), assess the outcomes resulting from these stressors and suggest ways to reduce stress and burnout. A representative sample of MAGAV officers (N=497) responded to a questionnaire at the height of the Palestinian violent uprising and a time of unusually high stress; 18% were interviewed. At the top of the list of stressors reported by the officers were: low salary, lack of resources and overload. This is significant in light of the finding that 74% reported a traumatic experience (such as a terrorist attack), 52% reported high or very high levels of stress (as compared to 32% reported by blue police officers) their burnout level was high (4.15 as compared to the national burnout level of 2.8 and 3.05 found during the same period of time among blue police officers). Despite the high stress of their work, the officers evaluation of their work was high and they expressed satisfaction from their work. These findings can be explained by the officers' feeling that their work is important. Coping strategies offered by MAGAV officers are outlined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)