The structure of graphite bombarded with light,gaseous ions

Natural and highly-oriented pyrolytic graphite crystals have been injected with helium, deuterium and carbon ions at energies up to 100 keV and doses up to 10¹⁸ ions/cm². This results in twinning in thick samples, the density of twinning increasing with energy and dose, and varying with target temperature. Twinning is shown to provide an important plastic deformation mode and a model of twinning related to the depth variation of atomic displacements is presented: a method of calculating the strains involved is discussed. It is suggested that surface distortions observed in other graphites originate in the same way. Measurements show that some gas is retained in the samples, but its direct role is uncertain. Very thin (thickness ? 0.1 μm) crystals blister under gas-ion bombardment and are demonstrated to retain sufficient gas to produce the blisters observed. It is shown that the blisters can grow laterally by cleavage in graphite, rather than by increasing their curvature and bursting as in metals. The origin of these blisters is obscure.     

Effect of photoperiod upon age and maintenance of sexual development in female Coturnix coturnix japonica

Coturnix kept in a 14L:10D photoperiod from hatch began to lay their first eggs at a mean age of 42.8 days (range 38-55). Approximately 2/3 of Coturnix held from hatch in photoperiods of 6L:16D light were laying at 165 days of age. Mean age at first egg was 112.7 days (range 68-162 days) in 8L:16D and 130.8 days (range 117-158 days) in 6L:18D photoperiod. Coturnix transferred from a non-stimulatory (8L:16D) photoperiod to a stimulatory one (14L:10D or 24L) begun laying in 15-20 days if less than 140 days old, and in about 5 days if greater than 140 days old, when trasferred. Birds which has spontaneously begun to lay in an 8L:16D photoperiod did not stop laying when the photoperiod was reduced to 6L:18D. Those which began laying under 14L:10D photoperiod ceased laying in about 15 days if 89 or fewer days old when switched to 8L:16D, or in about 6 days if 140 or more days old. Those switched from 14L:10D to 6L:18D ceased laying in about 13 days when 76 days old, and 7 days when 89 days old.     

Goal-directed guidance of attention: Evidence from conjunctive visual search.

Conjunctive visual search is most difficult when distractor types are in equal proportions and gets easier as the proportions diverge (e.g., E. Zohary & S. Hochstein, 1989). This may reflect restriction of search to the feature shared by the target and the less-frequent distractor. Alternatively, such effects could reflect target salience, which varies with distractor ratio. In 2 experiments, 60 participants searched 64-element displays for a conjunctive target among distractors of 2 types in various proportions. Participants were correctly informed (Experiment 1) or misinformed (Experiment 2) about which distractor type would be less frequent on most trials. In both experiments, the distractor-ratio effect was significantly influenced by the information provided to participants. These findings demonstrate the efficacy of top-down information in guiding attention and show that it can be applied flexibly, weighted toward particular target features. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sequential statistical design strategy in an experimental kinetic study

The value of using a sequential statistical design strategy is illustrated through its use in an experimental kinetic study of the oxidation of o-xylene over a vanadium oxide catalyst. The rate of oxidation of o-xylene was determined in a differential reactor over the following ranges of conditions: 270 to 300°C, (0.5 to 3.5) x 10^-4 g.mole o-xylene/1., (1.0 to 10.0) x 10^-3 g.mole oxygen/1. The statistical design strategy for precise parameter estimation was found to be effective in increasing the precision of the parameter estimates, in reducing the correlation between parameter estimates and in showing the magnitude of this problem, and in providing a reliable prediction of the value of carrying out additional runs.     

Aversive conditioning in neonatal kittens.

Trained 45 kittens less than 10 days of age to crawl over a barrier in a 1-way shuttle box either to escape or avoid pressurized air. Both instrumental escape and avoidance learning occurred. Escape performance was an increasing negatively accelerated function of air pressure. Avoidance behavior was not as stable or of the same form as that previously observed in infant dogs. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of hypophysectomy on calcium transport by rat duodenum

To examine the effect of hypophysectomy on intestinal calcium absorption, studies were performed on immature rats 7, 14, and 21 days after hypophysectomy. Duodenal calcium transport was measured in vitro utilizing everted gut sacs and in vivo by a luminal perfusion technique. Hypophysectomy produced no differences in the ability of everted gut sacs to transport calcium. Similarly, when in vivo transport data were expressed on the basis of intestinal length, no significant differences were noted. However, when transport data were expressed on the basis of mucosal weight, increases in absorption and lumen-to-plasma fluxes were apparent in hypophysectomized animals. No differences were seen in plasma-to-lumen fluxes. The results indicate that when the transport data are corrected for mass of intestinal mucosa, the duodenum from hypophysectomized animals absorbs calcium more avidly due to an increase in lumen-to-plasma flux.     

A cross-cultural study of correlates of crime.

In a sample of 48 nonliterate societies, frequency of theft and personal crime were separately correlated wtih a number of variables which were suspected to be casual factors in the development of crime. Lack or limitation of opportunity for the young boy to form an identification with his father was associated with both types of crime. A high degree of socialization anxiety in childhood and a high degree of status differentiation in adulthood were significantly associated with theft only; a general adult attitude of suspicion and distrust was more decidedly associated with personal crime. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Possible cholestatic injury from ranitidine with a review of the literature

BACKGROUND: Controversy persists regarding primary sclerosing cholangitis (PSC) as a risk factor for colorectal carcinoma in patients with chronic ulcerative colitis. Small sample size and differing endpoints have contributed to variation among reported studies. This large case-control study was conducted to examine the possible association between PSC and colon carcinoma in patients with ulcerative colitis. METHODS: From Mayo Clinic records spanning 1976-1994, 171 cases with both ulcerative colitis and colorectal carcinoma and 171 contemporaneous controls with ulcerative colitis but no colorectal neoplasia matched with regard to age, gender, extent, and duration of colitis were identified. The diagnosis of PSC required cholangiographic confirmation. Analysis employed a multivariate logistic regression model. RESULTS: The prevalence of PSC was similar in cases (18%) and controls (15%) (P = 0.54). The adjusted odds ratio for colorectal carcinoma with PSC was 1.23 (95% confidence interval, 0.62-2.42). CONCLUSIONS: Based on this large case-control study, there was no association between PSC and colorectal carcinoma in patients with ulcerative colitis.     

Confidence level and feeling of knowing for episodic and semantic memory: an investigation of lorazepam effects on metamemory

The effects of lorazepam (0.026 or 0.038 mg/kg), a benzodiazepine, and of a placebo on metamemory, i.e. knowledge about one's own memory capabilities, were investigated in 36 healthy volunteers. Accuracy of confidence levels (CL) in the correctness of recalled answers and accuracy of feeling of knowing (FOK) the answers when recall fails were measured using a sentence memory task assessing episodic memory and a task consisting of general information questions and assessing semantic memory. Lorazepam impaired episodic memory. Unexpectedly, it also impaired performance in both the recall and recognition phases of the task assessing semantic memory, suggesting that it decreased the ability to distinguish between correct and incorrect information. In episodic memory, lorazepam 0.038 mg/kg-treated subjects exhibited an impaired CL accuracy, compared to placebo-treated subjects, and their FOK accuracy was at chance. In semantic memory, their overall CL and FOK accuracy was apparently spared. However, these subjects selectively overestimated their CL judgements for incorrect answers; moreover, secondary analyses showed that FOK accuracy for a subset of low-accuracy items was virtually nil. These results suggest that lorazepam impairs metamemory for both episodic and semantic memory.