Increased Vulnerability to Stress Following Opiate Exposures: Behavioral and Autonomic Correlates.

The authors used rats to study the impact of a history of opiate exposures on behavioral and autonomic responses to restraint stress. Brief restraint (30 min) provoked tachycardia and a pressor response, anxiety (as indexed by social interaction), grooming, and reduced exploration. The pressor response was reduced at 1 day, but not 7 days, after last opiate exposure; tachycardia was unaffected (Experiment 1). Stress-induced anxiety was potentiated 1 and 7 days after last opiate exposure (Experiment 2), and this potentiation was a function of dose (Experiment 3) and duration (Experiment 4) of opiate exposure. The results show that a history of opiate exposures alters vulnerability to stress and has implications for understanding coping, anxiety, and emotionality in former opiate users. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Teachers' and Pupils' Behavior in Large and Small Classes: A Systematic Observation Study of Pupils Aged 10 and 11 Years.

The authors examined class size effects on teacher-pupil interactions, pupil engagement, and pupil-pupil interaction. They extended previous research by recognizing the hierarchical nature of observation data and the possible influence of other variables. The study used a time sampling method involving 257 children (aged 10-11 years) in 16 small (25 or under) and 26 large (31 and over) classes. In small classes, there were more individualized task-related contacts between teacher and pupils and a more active role for pupils. These results confirmed those from earlier research on children aged 4 and 5 years. Against expectation, class size did not affect pupil on-task behavior or peer interaction. There was a moderating role for school subject and a beneficial effect of teaching assistants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Computer hacking,myth or menace,part II

This article concludes a two part theoretical study of the problem of hacking, considering strategies of computer crime control, the changing face of social order and policy implications that these generate.     

The effect of a new approach to group work on pupil-pupil and teacher-pupil interactions.

The main impetus for the SPRinG (social pedagogic research into grouping) project was to address the wide gap between the potential of group work and its limited use in schools. It is an ambitious project that developed key principles and strategies to improve the effectiveness of group work in everyday primary classes and across a whole school year. On-the-spot and video-based systematic observations showed more active, sustained engagement, more connectedness, and more higher order inferential joint reasoning within SPRinG groups than in control comparisons. The authors argue that group work can be successfully implemented into everyday school classrooms and improve pupil interactions, provided teachers take time to train pupils in the skills of group working. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Diagnosing anal sphincter injury with transanal ultrasound and manometry

PURPOSE: This study was undertaken to evaluate how well anorectal manometry and transanal ultrasonography diagnose anal sphincter injury. METHODS: Anorectal manometry and transanal ultrasonography were performed in 20 asymptomatic nulliparous women and 20 asymptomatic parous women, and the results were compared with those obtained in 31 incontinent women who subsequently underwent sphincteroplasty and, thus, had operatively verified anal sphincter injury. By using computerized manometry analysis, mean maximum resting and squeeze pressures, sphincter length, and vector symmetry were determined in all women. All transanal ultrasounds were interpreted blinded as to the patient's history, physical examination, and manometry results. RESULTS: Manometric resting and squeeze pressures were significantly higher in the asymptomatic nulliparous women than in the asymptomatic parous women, and both groups had significantly higher pressures than the incontinent women (P < 0.001). Anal sphincter length and vector symmetry index were significantly decreased in incontinent women compared with asymptomatic women (P < 0.01). Decreased resting and squeeze pressures suggestive of possible sphincter injury were found in 90 percent of incontinent women with known anal sphincter injury. Decreased anal sphincter length and vector symmetry were found in only 42 percent of women with known anal sphincter injury. Transanal ultrasound was able to identify 100 percent of the known sphincter injuries but also falsely diagnosed injury in 10 percent of the asymptomatic nulliparous women with intact anal sphincters. False identification of sphincter injury increased when transanal ultrasound scanning was performed proximal to the distal 1.5 cm of the anal canal. CONCLUSION: Although nonspecific, decreased resting and squeeze pressures were found in 90 percent of patients with anal sphincter injury. Decreased anal sphincter length or vector symmetry index were present in only 42 percent of patients with known sphincter injury. When limited to the distal 1.5 cm of the anal canal, transanal ultrasound identified all known sphincter injuries but falsely identified injury in 10 percent of women with intact anal sphincters. Transanal ultrasound in combination with decreased anal pressures correctly identified all intact sphincters and 90 percent of known anal sphincter injuries.     

Accuracy and reliability of transanal ultrasound for anterior anal sphincter injury

INTRODUCTION: Although transanal ultrasound has rapidly become the test of choice for the diagnosis of anal sphincter injury, the accuracy and reliability of this technique are unknown. This study evaluates the accuracy and reliability of transanal ultrasound for anterior (obstetric-related) anal sphincter injury. METHODS: Sixty-two women underwent transanal ultrasound with hard-copy images obtained at 0.5-cm intervals from the anal verge to 2.5 cm into the anal canal. All transanal ultrasound procedures were also recorded on videotape. Two experienced ultrasonographers blinded as to the patients' clinical history and examination independently reviewed the images and videotape recordings for the presence or absence of anal sphincter injury. RESULTS: The accuracy of transanal ultrasound in 22 incontinent women with known anal sphincter injury was 100 percent. The accuracy of transanal ultrasound in 20 nulliparous women with intact anal sphincters was only 35 percent but improved to 50 percent after the "real time" videotape was reviewed (P = 0.16) and further improved to 85 percent when interpretation was limited to the distal 1.5 cm of the anal canal (P = 0.004). In these nulliparous women, intact internal sphincters were more accurately predicted than intact external sphincters (95 vs. 85 percent; P = 0.24). Measurement agreement between the two ultrasonographers was 68 percent (fair; kappa, 0.26) but significantly improved to 78 percent (moderate; kappa, 0.48; P = 0.0001) when interpretation was limited to the distal 1.5 cm of the anal canal. Overall clinical agreement (final scan interpretation) was good (81 percent agreement; kappa, 0.61). Agreement was better for the internal sphincter (74 percent; fair; kappa, 0.36) than the external sphincter (61 percent; poor; kappa, 0.17; P = 0.0002). CONCLUSIONS: Although transanal ultrasound can accurately identify anterior anal sphincter injury when present, transanal ultrasound falsely identifies sphincter injury in at least 5 to 25 percent of normal anal sphincters. Only fair agreement in the interpretation of transanal ultrasound exists between experienced ultrasonographers. Both the accuracy and reliability of transanal ultrasound are significantly improved by limiting transanal ultrasound to the distal 1.5 cm of the anal canal.     

Distribution of milk in the goat mammary gland and its relation to the rate and control of milk secretion

Changes with time in the distribution of milk between different storage regions of the mammary gland were studied in goats. Milk was allowed to drain from the gland through a catheter (catheter milk); the gland was then milked by hand, before (hand milk) and after the administration of oxytocin (alveolar or residual milk). The hand-milk fraction was of negligible volume. There was an essentially linear increase in the catheter-plus hand-milk fraction from 0 to 16 h. The alveolar fraction increased up to 6 h, but thereafter remained constant to 16 h. There was considerable but consistent variation between animals in the alveolar fraction as a proportion of total milk volume. The proportion of residual milk was inversely related to milk secretory rate per unit weight of mammary tissue. The hourly administration of oxytocin without milking had no apparent effect on the distribution of milk in the gland 1 h later.     

Formation of pre-silicide layers below Ni1−xPtxSi/Si interfaces

The formation of a pre-silicide layer below Ni_1?xPt_xSi films is reported with structure and composition distinctly different from previously observed diffusion layers. It was found that during two-step rapid thermal annealing Ni interstitial diffusion can kinetically dominate over the formation of Ni silicide, which results in a metastable pre-silicide layer. Aberration corrected scanning transmission electron microscopy experiments have revealed Ni to occupy interstitial and substitutional sites in the pre-silicide layer. Rapid thermal annealing and Pt alloying determines the stoichiometry and thickness of the layer, while the point defect configurations give rise to lowering of the associated Schottky barrier heights. The pre-silicide layer effectively limits diffusion of Ni into the substrate and therefore allows for the low-temperature growth of Ni₂Si and NiSi.