Natural history of sucking patterns in infant goats: A comparative study.

Examined temporal organization of sucking patterns, the phase interaction of sucking and other rhythmical motor patterns, and the effects of feeding on sucking rate in 26 Nubian goats. No changes in sucking rate were noted over the 1st 3 mo. The precise rate concordance between sucking and tail movements suggested that peripheral motor rhythms are regulated by a central sequencing mechanism which in turn is modulated by organismic and peripheral factors. A comparison of sucking patterns in 10 human infants and Ss indicates that qualitative species differences in the prefunctional organization of sucking influence the nature of the interaction between sucking performance and organismic or peripheral factors. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microcounseling for a counseling-like verbal response set: Differential effects of two micromodels and two methods of counseling supervision.

Compared the use of 2 models employing behavioral supervision and recall interrogation in teaching a counseling-like verbal response set to 16 guidance students. Pre-post1 and pre-post2 criterion performance gains of the experimental Ss and a no-treatment control group (n = 14) were measured on the Counselor Verbal Response Scale. Results from a 2 * 2 factorial design with a single control group reveal that microcounseling Ss gained significantly more in criterion performance than the controls. There was virtually no difference in the effectiveness of the 2 micromodels, and behavioral supervision was somewhat more successful than recall interrogation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in oxytocin and cortisol levels in primiparous cows after changing from 21 days of suckling calves to machine milking

Four first-calvers of the Black-Pied breed with calves sucking their milk until day 21 of lactation were included in a trial. One suckler cow had four calves. The trial took place within five days which included days 20 and 21 in the first-calvers, that means the last two days with sucking calves (designated as day 1 and day 2 of trial-first and second calf sucking) and days 22 and 24, that means the first and third day after the cows were moved to a cowshed (designated as the third and fifth day of trial-first and third evening machine milking). The first-calvers were separated from the calves and moved to a cowshed at 8 o'clock a.m. on day 3 of trial (Tab. I). The responses to calf sucking were investigated after four-hour prevention of calves to approach the cows (12.00-16.00 p.m.). Blood was sampled with a catheter which was introduced into the vena jugularis a day before the trial outset. Blood samples for cortisol determination were taken in two-hour intervals (when the cows were moved to the cowshed twice in half-an-hour interval and once in an hour interval). Blood samplings were effectuated by day, before, during and after milking, or sucking. Machine milking was finished within 7 to 8 minutes. Two to four calves were intensively sucking a cow within the first 15 minutes, then sucking was irregular. Plasma samples were deep-frozen and stored at -20 degrees C until determinations were performed. Oxytocin and cortisol in the blood plasma were determined by radioassays. In the first evening machine milking (day 3) the second cow yielded 8.23 kg milk while on day 5 in the third milking it was 7.98 kg. The other first-calvers gave by 30-45% less milk on day 3 in comparison with evening milking on day 5 (Tab. II). A trend of the higher average values of oxytocin was observed in machine milking on day 5 of trial if compared with the values recorded during calf sucking, or the first milking (day 3), Fig. 1a, Tab. III. The mean oxytocin concentration during 7-minute milking (12.39 +/- 5.81 pg/ml) was significantly lower in the first-calvers on day 3 in comparison with the mean values recorded on day 5 (28.01 +/- 18.56 pg/ml; P < 0.001), or during sucking (18.32 +/- 7.15 pg/ml; P < 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)     

Mechanics and energetics of nutritive sucking: a functional comparison of commercially available nipples

The purpose of this study was to compare the mechanics of sucking for 48 term infants with four different nipple units: Gerber Newborn (Gerber Products Company, Fremont, Mich.), Playtex (Playtex Products, Westport, Conn.), Evenflo (Evenflo Products Co., Canton, Ga.), and Gerber NUK. At 24 hours after birth, infants were assigned randomly to one of the nipple units and were studied twice with that nipple unit. A customized data acquisition system was used to measure and record the following variables: intraoral suction, sucking frequency, work, power, milk flow, milk volume per suck, and oxygen saturation. Although no statistically significant differences among the nipple units were noted for intraoral suction, sucking frequency, power, and oxygen saturation, the data revealed that the Playtex nipple unit was accompanied by higher peak milk flow and greater volume of milk per suck (p < 0.05). Infants fed differently with the Playtex nipple than they did with the other nipples. Our findings indicate that the Playtex nipple permits a greater milk flow in response to similar amounts of suction, work, and power when compared with others. The mean total work per such was significantly lower in the Gerber NUK group compared with the Playtex group. In addition, the total number of sucks per volume ingested was higher, and the total time to ingest a specific quantity of milk was longer for the Gerber NUK nipple.     

Oral feeding in low birth weight infants

To gain a better understanding of the development of sucking behavior in low birth weight infants, the aims of this study were as follows: (1) to assess these infants' oral feeding performance when milk delivery was unrestricted, as routinely administered in nurseries, versus restricted when milk flow occurred only when the infant was sucking; (2) to determine whether the term sucking pattern of suction/ expression was necessary for feeding success; and (3) to identify clinical indicators of successful oral feeding. Infants (26 to 29 weeks of gestation) were evaluated at their first oral feeding and on achieving independent oral feeding. Bottle nipples were adapted to monitor suction and expression. To assess performance during a feeding, proficiency (percent volume transferred during the first 5 minutes of a feeding/total volume ordered), efficiency (volume transferred per unit time), and overall transfer (percent volume transferred) were calculated. Restricted milk flow enhanced all three parameters. Successful oral feeding did not require the term sucking pattern. Infants who demonstrated both a proficiency > or = 30% and efficiency > or = 1.5 ml/min at their first oral feeding were successful with that feeding and attained independent oral feeding at a significantly earlier postmenstrual age than their counterparts with lower proficiency, efficiency, or both. Thus a restricted milk flow facilitates oral feeding in infants younger than 30 weeks of gestation, the term sucking pattern is not necessary for successful oral feeding, and proficiency and efficiency together may be used as reliable indicators of early attainment of independent oral feeding in low birth weight infants.     

Effects of knowledge of criterion groups on actual and expected test performance of Negro and Mexican-American eighth graders.

Examined the effects that knowledge of the criterion group had on the test performance of 102 Negro and 74 Mexican-American 8th graders. There was no evidence that comparison with 1 of 4 norm groups affected performance through either an Aptitude * Treatment interaction or through an overall treatment effect. Data on expected performance indicate a significant aptitude-treatment effect with Negro Ss only. Results suggest that knowledge of a criterion group may not consistently alter the test performance of persons from minority groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of intermittent, moderate intensity noise stress on human performance.

Studied the effects of prolonged exposure to 2 noise stressors (random and patterned intermittent 0 and 85 db) on the performance of 60 male undergraduates on 3 tasks requiring different abilities (reaction time, rate control, and time-sharing). The sensitivity of alternate metrics of performance degradation was also evaluated within an analysis of covariance design. Ss were randomly assigned to the various treatments, and a series of 2 * 2 * 4 (Noise Intensity * Noise Quality * Trial Blocks) covariance analyses were carried out. The effects of random noise on performance depended on the type of task and performance measure. The reaction-time task was affected, the rate-control task was not, and the time-sharing task was affected only after continued exposure to noise. Patterned noise had insignificant effects. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predictive value compared to predictive validity.

Previous studies have found validity coefficients for 2 * 2 tables to be quite large, even though the predictor would yield as many errors as the blanket prediction. In the present study, 81 combinations of predictor and criterion dichotomies were analyzed using artificial data in the form of 2 * 2 tables. Phi coefficients were compared with Goodman and Kruskal's lambdas, which indicate the percentage reduction of prediction errors. It was found that lambda was 0 for nearly 1/2 of the 2 * 2 tables generated to yield nonzero phis. Phi and lambda were equal when the predictor and criterion dichotomies were both 50-50. Under most other dichotomies, lambda was much less than phi, suggesting that the difference between the tetrachoric r (rtet) and lambda would be even greater. It is concluded that when the 2 kinds of prediction errors are considered to be equally costly, phi and rtet should not be used to assess predictive value unless the criterion dichotomy is between 40 and 60 and 60 and 40. When "false rejections" are considered to be unimportant, phi and rtet should not be used unless the base rate is .5 or greater. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ability requirements as a function of changes in the characteristics of an auditory signal identification task.

Examined the nature of changes in abilities contributing to individual differences in a criterion task (auditory signal identification) when 2 task characteristics (signal duration and signal-to-noise ratio) were systematically varied. 127 male college students performed under 9 different conditions on the criterion task (3-, 6-, or 9-sec signal durations, and -5 db, 0 db, and 5 db signal-to-noise ratios), as well as on a battery of 24 printed and auditory ability measures (e.g., Object-Number, Gestalt Completion, and Hidden Tunes tests). Variations in the 2 task characteristics were found to increase task difficulty. Of the 6 ability factors identified, one (Auditory Perceptual) predicted criterion task performance, and this prediction increased systematically as each manipulation increased the task's difficulty. It was possible to specify the task characteristics under which the ability was least critical and most critical to criterion performance. Implications of the results for linking ability requirements and task characteristics are discussed. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Speech as reinforcing stimulation for infants.

32 5-15 wk old infants were exposed to 1 of 4 experimental conditions that involved (a) the presentation of natural speech stimuli contingent on the infants' nonnutritive sucking, (b) the withdrawal of speech stimuli contingent on the infants' nonnutritive sucking, (c) the noncontingent presentation of speech stimuli, and (d) no speech stimuli. Only the presentation of speech stimulation contingent on the infants' nonnutritive sucking resulted in a significant change in the rate of such sucking compared to infants receiving no sound stimulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of vagal activity on classically conditioned heart rate in rats.

Examined the relative contributions of parasympathetic and sympathetic activity in controlling classically conditioned heart rate (HR) in 112 female Long-Evans rats in a 2 * 2 * 2 factorial design involving comparisons of the following factors: (a) conditioning vs sensitization, (b) vagal blockade vs nonblockade, and (c) acquisition vs extinction. Vagal blockade led to a substantial reduction in the performance level of the decelerative HR CR, but it did not appear to interfere with the learning of the CR as measured during extinction under saline. It is concluded that the magnitude of the CR was primarily mediated by increased vagal activity and that sympathetic involvement was minor. Results are related to a central state hypothesis which links together decelerative conditioned HR and inhibition of motor activity in the rat. (23 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of a preferential relationship with the mother by the newborn lamb: importance of the sucking activity

Lambs develop a preferential relationship with their mothers within 24 h after birth. In a first experiment, we attempted to determine whether neonatal sucking was a potent reinforcer in the establishment of this preference by temporarily covering the udders of ewes after parturition. Lambs were assigned to one of three treatments: they had free access to the udder (group 1) or were prevented from sucking either between birth and 6 h afterward (group 2) or between 12 and 18 h after birth (group 3). Measurements of cholecystokinin plasma levels at birth and at 6 and 18 h showed that all lambs ingested some colostrum when the udder was made accessible. When tested in a two-choice test situation at 24 h of age, lambs from group 1 spent significantly more time near their mothers than near the alien ewes, those from group 2 did not show any discrimination, and lambs from group 3 clearly preferred the alien ewes. At 2 days of age, lambs from groups 1 and 3 showed a strong preference for their mothers, whereas those from group 2 still displayed no preference. In a second experiment, we attempted to determine whether sucking also had a reinforcing value in the maintenance of this preference. Lambs were assigned to one of three treatments: they had free access to the udder (group 1) or were prevented from sucking for 6 h either at birth (group 2) or at the age of 3 days (group 3). Lambs from group 2 did not discriminate between their own and alien dams when tested at 24 h of age, unlike those of groups 1 and 3. When a second test was performed at 4 days of age, all the lambs showed a strong preference for their dams. We concluded that sucking has strong rewarding properties in the establishment of a preferential relationship with the mother by the lamb. On the other hand, the maintenance of this preference does not rely on sucking as strongly.     

Effect of a traditional and of a new nipple shield on sucking patterns and milk flow

The effect of a traditional (Mexican Hat) and of a new (Thin Latex) nipple shield on the sucking patterns and milk intake of 5-8-day-old babies was examined. Milk intake was determined accurately by test weighing using a Sartorius electronic balance with animal weighing keyboard, and sucking patterns by filming the mouth of the baby. The Mexican Hat reduced milk transfer by 58% (P is less than 0.01), and increased sucking rate (P is less than 0.05) and time spent resting (P is less than 0.01). The Thin Latex nipple shield reduced milk intake by a smaller amount (22%), and had no significant effect on sucking patterns.     

Electromyographic patterns associated with nonnutritive sucking in 11–13-day-old rat pups.

Three experiments used an EMG technique to measure the frequency, duration, and intensity of nonnutritive sucking (NNS) in 56 11–13 day old Wistar pups. Ss were separated from their mothers for 2–6 or 20–24 hrs and then allowed to suckle an anesthetized dam for up to 3 hrs without receiving any milk. Jaw-muscle EMG and nipple detachments were recorded. EMG patterns representing 2 discrete modes of sucking were reliably discerned, as were changes in overall intensity of EMG. 20–24 hr separated Ss engaged in more frequent NNS bouts and bouts of longer duration than 2–6 hr separated Ss. Ss separated by 20–24 hrs also engaged in a mode of NNS not seen in 2–6 hr separated Ss. Overall EMG intensity was higher and frequency of nipple detachments was lower in Ss separated for 20–24 hrs. In both groups, but particularly the 20–24 hr Ss, frequency of some NNS patterns decreased as the length of the "dry" suckling increased. EMG intensity also decreased over time in both groups, and frequency of nipple detachments increased in 2–6 hr separated Ss. Data indicate that some aspects of NNS are highly labile and respond to variations of both deprivation from the mother and nutritive deprivation. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of goal setting and supervision on worker behavior in an industrial situation.

Investigated the effects of goal setting by supervisors on 4 performance criteria. A factor analysis of a questionnaire administered to 292 pulpwood producers indicated that goal setting is correlated with high productivity and a low number of injuries only when it is accompanied by supervision. Goal setting without immediate supervision was related to employee turnover. Supervision alone did not correlate with any performance criterion. No relationship was found between the 2 job behaviors and absenteeism. The factor analysis results pertaining to productivity were partially corroborated in a 2nd study involving data collected from 892 additional producers. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ability of newborn infants to discriminate sapid substances.

Observed taste preferences in newborn infants to determine (a) the ability of newborns to discriminate different sapid substances and different molar concentrations within those substances and (b) the role of immediate prior sucking and ingestion experience in altering subsequent oral behavior. Ss were 48 male and 48 female full-term, single birth 1-3 day old infants. Results show that the sucking rate varied with the substance (glucose, sucrose, and water) delivered through the nipple and with the order in which the substances were presented within a test session. Amount of fluid delivery was controlled automatically by the infant's own sucking behavior, a procedure which provides a taste preference report as well as evidence of the discriminability of taste substances. It remains to be demonstrated that profound taste aversions, resulting in complete inhibition of sucking, are also present at this young age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of sentence complexity on the reading comprehension of syntactic structures.

Studied the effects of sentence complexity on reading comprehension of the Minimal Distance Principle (MDP), a general psycholinguistic principle, in 102 3rd, 4th, and 5th graders. Ss were asked to identify subordinate clause subjects of sentences in a 2 * 2 factorial study with 2 levels of MDP (conforming and violating) and complexity (following and interrupting statements). Significant main effects were found for MDP (conforming sentences were easier) and complexity (following statements were easier). The MDP and complexity variables formed a significant interaction. The MDP-violating sentences produced performance characteristic of short-term memory tasks, making complex sentences, which separate subject and subordinate clause by several words, difficult to process. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in the relationship of attitudes toward technology to choice of field of study.

Investigated whether attitude toward technology would bear the same relationship to choice of college major for female (n = 150) and male (n = 106) college freshmen. Ss completed the authors' Mechanization Scale, an instrument which measures 5 aspects of attitudes toward technology. Ss were classified into a 5 * 2 * 3 (Major Field * Sex * GPA) design. Multivariate analysis of variance revealed significant differences between high-, median-, and low-GPA groups for major field, sex, and Major Field * Sex interaction. A discriminant analysis revealed that the relationship of mechanical curiosity to choice of major field was consistent for both males and females. However, the sexes did not overlap on mechanical curiosity. This finding is discussed as an example of test bias for a nominal criterion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Validation of a less-invasive method for measurement of serotonin synthesis rate with alpha-[11C]methyl-tryptophan

We tested in normal human subjects a less invasive method to obtain plasma input function required in the calculation of the brain serotonin synthesis rate measured with positron emission tomography (PET) and alpha-[11C]methyl-tryptophan (alpha-MTrp). The synthesis rates derived with the arterial input function were compared to those derived from venous plasma and venous sinus time-radioactivity curves obtained from dynamic PET images. Dynamic PET images were obtained for the lengths up to 90 minutes after an injection of alpha-MTrp (400 to 800 MBq). Input functions were generated from both artery and vein in three subjects, and from artery only in two subjects. Net unidirectional uptake constants of alpha-MTrp (K*; mL/g/min) were calculated in several brain regions graphically using data between 20 and 60 minutes after injection with different input functions. In the five subjects with arterial sampling, we tested two methods for correcting the input functions from the venous samples: (1) normalization to the mean exposure time at 20 minutes from arterial curve; and (2) the use of the venous sinus curve for the first 20 minutes. Venous curves coincided with the arterial ones after about 20 minutes. When the venous curves were used, there was an underestimation of the area under the curves up to 20 minutes, resulting in a 5% to 30% overestimation of K* values. Combined use of the sinus curve up to 20 minutes and venous curve from 20 to 60 minutes as an input function resulted in the K* (mL/g/min) values larger by 7.1 +/- 3.8% than the K* values estimated with the arterial input function. Normalization of the venous curve to the exposure time at 20 minutes obtained from the arterial plasma curve resulted in a bias in the K* of about -0.34 +/- 3.32%. The bias from the K* values was propagated to the serotonin synthesis rates. The use of a combination of the venous blood samples and venous sinus as the input function resulted in an acceptable bias in the serotonin synthesis rates from the tissue time-radioactivity curves generated by PET.