Source of cues for cue-dependent amnesia in rats.

In 2 experiments 54 Sprague-Dawley male albino rats were given extensive training in a complicated appetitive maze and then handled extensively for 7 days. On the 7th day of the retention interval some Ss were exposed to the "cognitive" learning cues of the maze and some were not. Immediately afterward Ss were given ECS or sham ECS. To the extent that cognitive learning cues are assumed to activate memory, the ECS impaired retrieval of memory only for those Ss which had the cues reinstated prior to ECS administration. It appears that memory must be active at the time of ECS in order to obtain retrieval deficits. In a 3rd experiment with 36 Ss the intensity of hunger drive, manipulated by the amount of prefeeding, was not a cue for memory activation and subsequent cue-dependent amnesia. Arousal is therefore not believed to be crucial for the effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Investigation of 9.6 kb/s data transmission via a pcm link at 64 kb/s with and without link errors

The problem of pulse code modulation (PCM) bit errors causing voice frequency (VF) modem errors has been studied in detail. The error mechanism consists of the addition of an impulse response type error signal added to the reconstructed VF data signal waveform at the digital-to-analogue (D/A) output of the PCM decoder. This error signal may cause a burst of errors registering in the VF modem receiver, depending on which PCM bit is in error. Numerous data have been collected in a laboratory experiment and analysed in various ways. The average bit error rate (BER) enhancement factor of VF data over PCM is between 10 and 20. For each PCM bit in error, an average of two VF data bits are in error. The analysis leads to suggestions for possible solutions to the problem.     

A failure to replicate the Bem and Allen study of individual differences in cross-situational consistency.

D. J. Bem and A. Allen (see record 1975-04252-001) purportedly found evidence that, by using self-report measures of cross-situational consistency as moderator variables, it was possible to substantially increase the size of correlation coefficients computed among measures of each of 2 personality traits. In the present study, 112 undergraduates were divided into high- and low-consistent groups using 3 methods. Within each group correlations were computed among and between 6 self-report measures, for each of 8 traits (e.g., friendliness, emotional stability). In general, none of the methods of consistency classification replicated the Bem and Allen finding. In cases where the high-consistent group had a larger average correlation among the measures than their low-consistent counterparts, the size of that difference was negligible. Moreover, there were about as many instances in which the low-consistent group actually had larger average correlations. There was essentially no agreement among the various consistency classification methods in dividing Ss into high- and low-consistent subsamples. (49 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nutrition labelling of foods: comparisons between US regulations and Codex guidelines

Nutrition labelling of food impacts not only on consumers and the food industry, but on international trade as well. When requirements for food label information are similar among countries, trade is facilitated. Comparisons between recent nutrition labelling regulations issued by the USA and the international guidelines formulated by Codex Alimentarius identify not only challenges to international harmonization that require focused efforts, but also opportunities for increasing international agreement on nutrition labelling. Factors to be considered are the continued benefits of a generalized Codex guideline as well as technical issues including analytical methods, nutrients to be declared, bases for declaration, and reference values.     

Quantification and identification of particle movement in epidermis after thermal injury

Skin samples from a rabbit hind limb were taken from controls and at 5 min, 2 and 6 hr after a mild thermal injury (60 degrees C for 1 min). Large aggregates of intercellular particles, usually ribosomal in appearance, were seen in 6 hr samples and were accompanied by some peripheral aggregates of particles and by granule-coated vesicles. These structures were present in earlier samples to a lesser extent and were absent from control material. Quantitative assessment showed that intercellular particles apparently increased up to 6 hr whereas peripheral aggregation was maximum at 2 hr. Histochemical analysis confirmed that the particles contained ribonucleoprotein. Other larger particles were seen occasionally and contained carbohydrate. Lymph draining the site showed cellular changes, little change in enzyme activities, and no aggregates of particles.     

Histone-histone interactions. I. An electrophoretic study

Whole histone extracted from chromatin by either acid or protamine displacement was found by gel electrophoresis at pH7 to contain only two histone complexes, H2A-H2B and H3-H4, and uncomplexed histone H1. Although both complexes are dissociated at low pH or with high urea concentrations, removal of the denaturant resulted in complete complex reformation within minutes at the most. A syntematic investigation of binary, ternary and quaternary histone mixtures revealed that interactions also occur between histones H2B-H4 and H2A-H4. No evidence however was found for the formation of ternary and quaternary histone complexes.     

The effect of interturn heat flow on the recovery currents of a superconducting magnet: A comparison of calculated and measured values

Cryostatic stabilization is appropriate for superconducting magnets producing steady fields over large volumes. The measured recovery currents for a 10 cm bore 6.4 T experimental solenoid are compared with values derived from a stability analysis which includes heat flow from the resistive region to adjacent conductors as well as to the helium coolant. Agreement is excellent despite some uncertainty in the helium heat transfer characteristic and in the thermal conductivity of the interturn insulation. Given good data for these it should be possible, using the method presented, to design cryostatically stabilized windings with precision just from basic data for the conductor and its intended environment.Details of the behaviour of large and small resistive regions in this solenoid are given. The critical currents are also accurately predicted from the performance of short samples of the conductor after taking account of anisotropy with respect to the direction of the ambient magnetic field.     

A comparison of the effect of two regimens of infestation on the development of resistance by cattle to the cattle tick, Boophilus microplus (Can.)

The development of resistance to Boophilus microplus by cattle was studied using sets of cattle twins, in stalls. One twin from each set received 3 infestations of 40,000 larvae and the other a continuous infestation of 1,000 larvae a day over the same period. Sets of twins were then challenged with 1,000 larvae a day for 40 days and 2 field infestations of 20,000 larvae. Correlations of ranking for resistance made at 40-day periods during daily infestations of 1,000 larval ticks or for corresponding intermittent infestations of 40,000 larvae were low until animals had received 120,000 larvae. Thereafter irrespective of method of infestation correlations of ranking were relatively high (r = 0.61-0.96) between periods of infestations or method of infestation including 2 field infestations. Fewer adult female ticks matured on the daily infested animals than on the intermittently infested animals during the treatment period, but animals developed a similar resistance level whether infested with either technique.