The claim that appropriate "after-event review (AER)" may increase the relative value of drawing lessons from successes, as compared with failures, was examined in the present study. The study was a laboratory experiment in which the effect of type of AER (failure-focused, success-focused, failure- and success-focused, and no AER review) on performance improvement and causal attributions was tested under conditions of earlier success and earlier failure. In general, 2 results were demonstrated: (a) Drawing lessons from successful experience is feasible, and its effectiveness is contingent upon the type of AER. More specifically, after successful events, the most effective review is that of wrong actions, whereas after failed events, any kind of event review (correct or wrong actions) is effective. (b) AERs elicit more internal (as opposed to external) and specific (as opposed to general) attributions. These 2 classifications moderate the effect of AERs on task performance.

The vibration perception threshold (VPT) was investigated by biothesiometry in 61 children (28 boys) with Type 1 diabetes, mean age 15.5 (range 10-21) years, duration of diabetes 6.9 (range 1-19) years, and in 76 healthy children (39 males), mean age 13.8 (range 10-19) years. The measurements were performed in triplicate on the right second finger and on the right first toe. The vibration perception threshold was significantly increased (p < 0.0001) in the young diabetic patients (mean +/- SD, finger 4.1 +/- 1.1 V, toe: 5.7 +/- 1.3 V) compared to healthy children (finger 3.4 +/- 0.9 V, toe: 3.6 +/- 1.3 V). Twenty percent of adolescents with Type 1 diabetes had a VPT above the 95th percentiles (finger: 5 V, toe 6.5 V) for normal control children. In healthy controls a significant correlation (r = 0.27, p < 0.01) was found for VPT in finger versus toe. This relationship was not significant in the diabetic group and may be due to reduced sensitivity of the fingertips caused by frequent blood glucose testing. Age, Tanner stage and height were significantly correlated to VPT (toe) in both diabetic and normal boys, while duration of diabetes, HbA1c, arterial blood-pressure and body mass index were not significantly associated with VPT in any of the groups. The results indicate that changes in VPT appears early in childhood and emphasize a need for further studies of subclinical neuropathy in young patients with Type 1 diabetes.

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The second equilibrium ion pair acidity constants (pK,) of 9,1O-dihydroanthracene, 9-phenyl-9,lOdihydroanthracene, 9,1O-diphenyl-9,1O-dihydroanthracene and 9-cyano-9,lO-dihydroanthracene with sodium, potassium and rubidium have been determined in tetrahydrofuran (THF) at 25°C in the concentration range 105-10-2 mol dm-3. Equilibria were monitored by UV-VIS and 'H NMR spectroscopies and the spectra of the dimetallic and monometallic salts reported. The dimetallic salts of all the dibasic carbon acids studied behave as contact ion pairs in THF. The pK, of 9,lO-dihydroanthracene is insensitive to substituent effect but is strongly dependenton the cation.Dianions and polyanions are widely used for organic syntheses. ' For this reason, information concerning methods of Paper 4/008351

The geometric structure, charge distribution and heats of formation of 9-R '-10-R2-9, 10-dihydroanthracenes R2 = H), their mono-and di-anions, deprotonated at positions 9 and 10 have been calculated by the AM-1 method. The 3C chemical shifts of the mono-and di-alkali metal salts have been determined in C2H, JTHF. The structures of the mono-and di-anions are nearly planar, the dianions being more planar than the monoanions. The hybridization of the deprotonated carbon atoms is nearly sp2. Phenyl substituents subtend angles of 56.5" and 45.0" to the anthracene plane in the mono-and di-anions, respectively. With the exception of the cyano group, there is little participation by the substituents in the delocalization of negative charge. There is a correlation between the n-electron densities and the change in 13C chemical shift upon anion formation from the neutral species. The values of the proportionality constants are equal to 120.3 and 133.1 ppm/electron for mono-and di-anions, respectively. The pattern of negative charge distribution in the monoanions of 9,lO-dihydroanthracenes is similar to that of substituted diphenylmethanes. The first and second acidity constants of substituted 9,lO-dihydroanthracenes in the liquid phase follow the patterns indicated by the gas phase calculations of their relative thermodynamic stabilities.