Ontogeny of suckling in rats: Transitions toward adult ingestion.

Studied the suckling behavior of neonatal Sprague-Dawley rats on their own anesthetized mother from the day of birth until after weaning (35 days). Even newborn Ss were capable of nipple attachment without maternal assistance. Before 11–23 days of age, pups deprived of suckling for 22 hrs and nondeprived pups quickly attached to their mother's nipples, sucked, and remained attached to the nipple though no milk delivery occurred. Then behavior underwent at least 3 changes: (a) After 11–23 days of age, latency to attach became considerably elevated in nondeprived pups; (b) a 2nd change in latency occurred at 23–25 days of age, when nondeprived pups no longer even attached to the nipples of anesthetized mothers; and (c) about 14 days of age, deprived pups began to shift from 1 nipple to the next after initial attachment. These developmental changes were seen in other test situations in which pups were placed directly on a nipple and not required to search and when various periods of deprivation were utilized. These transitions were not critically dependent on the onset of visual function or on the pup's experience with food other than mother's milk. Suckling, therefore, in not an unmodified reflex but is an appetitive behavior that undergoes a series of changes during development. These transitions constitute major developmental events in the ontogeny of rat ingestive behavior. (48 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Solvent fractionation of leaf juice to prepare green and white protein products

The effectiveness of organic solvents in the separation of pigmented protein from leaf juice was studied, thus permitting the recovery of a non-pigmented protein suitable for use in human foods. Juices extracted from lucerne (Medicago sativa L.), tall fescue (Festuca arundinacea L. var. Alta) and Italian ryegrass (Lolium multiflorum L. var. RVP) were studied. The yield of ?white’? protein from lucerne was double that from the grasses and it was lighter in colour. Of 20 solvents tested, 13 promoted the separation of chloroplastic material. These were in two categories: solvents with limited water solubility which were effective at a 3-4% (w/w) concentration and highly polar solvents which were effective at a 10-12% (w/w) concentration. Solvents of high specific gravity were not effective. Various conditions of solvent concentration, temperature and pH were studied with representatives of both groups of solvents in order to optimise the yield of ?white’? protein. Solvent fractionation, as a method of preparing a non-pigmented protein concentrate, is discussed in relation to differential heat treatment of leaf juice and solvent extraction of whole leaf protein concentrate. The potentials of these concentrates in human foodstuffs is compared.     

Inhibitors of cholesterol synthesis and myelin formation

Inhibitors of cholesterol biosynthesis AY 9944 and 20,25 diazacholesterol were administered by stomach tube to suckling rats in varying doses during the time of rapid myelination (15–22 days of age). Purified myelin was prepared from the brains and spinal cords, and the sterol content analyzed. Up to 50% of the myelin sterol consisted of desmosterol in rats treated with 20,25 diazacholesterol, while 7-dehydrocholesterol comprised at least one third of the myelin sterol in rats administered AY 9944. Myelin from rats treated with both compounds contained desmosterol, 7-dehydrocholesterol, Δ^5,7,24 cholestatriene-3-β-ol and an unknown sterol, the four comprising about 45% of the total sterol. The proportion of phospholipid: galactolipid-total sterol in myelin from the drug-treated rats was not significantly different from the normal, although much less myelin was recovered. Brain and spinal cord slices from 22 to 25-day rats pretreated with inhibitors showed decreased uptake of U-¹⁴C-glucose into all myelin components. The decreased uptake was approximately proportional in all lipids and the protein was also affected. It is proposed that myelin composition is fixed, and that a deficiency of one of the lipid components will limit the assembly of the whole lipid portion of the membrane. Presented at the AOCS Meeting, San Francisco, April 1969.     

Comparative study of the concepts of the French and the American guidance movement.

Under one form or another Vocational Guidance has existed down the centuries. Socrates guided Plato; Plato guided Aristotle; Aristotle guided Alexander the Great. However, it was only at the turn of this XX Century that vocational guidance became an organized movement reaching out to youths from every walk of life. Guidance counsellors became duly accredited professionals. What the concepts of vocational guidance were both in France and in the United States of America respectively from the turn of this XX Century is now being presented in the following article. Of special interest is the fact that national and state laws seconded the guidance movement both in France and in the United States. Education benefitted immensely by incorporating educational and vocational guidance into the vast ramification of its schools and institutions. A fuller grasp of the concepts of guidance in French and in the American educational systems helps unravel some of the knotty problems of the Guidance Movement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dopamine D? receptor activation modulates perceived odor intensity.

Dopaminergic modulation affects odor detection thresholds and olfactory discrimination capabilities in rats. The authors show that dopamine D? receptor modulation affects odor discrimination capabilities in a manner similar to the modulation of stimulus intensity. Performance in a simultaneous odor discrimination task was systematically altered by manipulations of both odorant concentration and D? receptor activation (agonist quinpirole, 0.025-0.5 mg/kg; antagonist spiperone, 0.5 mg/kg). Rats' discrimination performance systematically improved at higher odor concentrations. Blockade of D? receptors improved performance equivalent to increasing odor concentration by 2 log units, whereas activation of D? receptors reduced odor discrimination performance in a dose-dependent manner. Bulbar dopamine release may serve a gain control function in the olfactory system, optimizing its sensitivity to changes in the chemosensory environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

WISC-III predictors of academic achievement for children with learning disabilities: Are global and factor scores comparable?

The Wechsler Intelligence Scale for Children-Third Edition (WISC-III) provides a Full Scale Intelligence Quotient (FSIQ), four factor standard scores, and subtest scale scores. In contrast with previous findings, this study of 174 children (aged 6–16 yrs) meeting criteria for learning disabilities revealed that the WISC-III factors accounted for a large portion of achievement variance during hierarchical regression analyses, yet FSIQ added little predictive power. A commonality analysis of FSIQ indicated that it is largely comprised of unique, not shared, factor variance. Analyzing the WISC-III subtests from a fluid-crystallized (Gf-Gc) intelligence theoretical framework, academic achievement commonality analyses revealed complex relationships among the predictors, with crystallized, quantitative, and short-term memory factors accounting for the most achievement variance, regardless of academic domain. Results suggest that simple rejection of factor or subtest scores based on hierarchical regression techniques is unwarranted and that systematic exploration of nomothetic and idiographic patterns of performance is recommended for practitioners. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Low conductivity plasma sprayed thermal barrier coating using hollow psz spheres: Correlation between thermophysical properties and microstructure

Life and thermal properties of plasma sprayed TBCs - widely used in gas turbine engines - are closely related to the microstructure of the ceramic top coating. Especially, the thermal behaviour of this coating is induced by the void shapes and networks which are in turn determined by both the spraying conditions and the feedstock material.A specific hollow yttria partially stabilised zirconia powder was produced in a one-step process by spray drying and an experimental statistical design study was conducted to investigate the influence of spraying variables (primary and secondary gas flow rates, arc current, spraying distance, spraying angle and traverse speed) on structure and properties of resulting plasma sprayed coatings. The coatings were characterized with respect to deposition efficiency, roughness, porosity and thermal conductivity. A reduction of 25% of the thermal conductivity was achieved by improving the spray and powder parameters. A quantitative characterization of the porous structure using image analysis of polished cross-sections was implemented. The parameters that have relevant influence on the coating porous structure were identified, and their relative importance was determined. An attempt was made to identify morphological criteria of the porous network (coarse/fine porosity ratio, cracks total length, cracks orientation) correlating with the thermal conductivity values.     

Developmental issues in Chinese children's character acquisition.

Measures of phonological processing, speech perception, and Chinese character recognition were administered to 109 Hong Kong Chinese 3- and 4-year-olds. A model predicting phonological awareness from vocabulary, verbal short-term memory, and speech perception was supported. Both phonological awareness and letter naming predicted unique variance in character recognition after controlling for other phonological processing and vocabulary skills, similar to previous studies of Western readers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

From objects to quantities: Developments in preschool children's judgments about aggregate amount.

The impact of object boundaries on children's developing quantitative reasoning was examined in a study of children's judgments about aggregate amount. Children at ages 3, 4. and 5 years were asked to help a Cookie Monster get as much to eat as possible by choosing between alternative collections that differed in the number and size of the cookies they contained and also in aggregate amount. Results indicated that children were heavily influenced by the size of individual cookies at 3 years of age but were generally unsuccessful in aggregating size information across multiple cookies until 5 years. The contrast between children's sensitivity to object sizes from an early age and the relatively late achievement of accurate judgments of aggregate amount underscores the significance for quantitative development of the distinction between discrete objects and mathematical quantities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A new method of optimising material removal rate using EDM with copper–tungsten electrodes

Electrical discharge machining (EDM) is widely used in the production of dies. This paper describes an investigation into the optimisation of the process which uses the effect of carbon which has migrated from the dielectric to tungsten–copper electrodes. This work has led to the development of a two-stage EDM machining process where different EDM settings are used for the two stages of the process giving a significantly improved material removal rate for a given tool wear ratio.