Level of processing as a determinant of hypnotic hypermnesia.

Reconceptualized the distinction between those situations in which one can and cannot expect to observe hypnotic hypermnesia using the levels-of-processing theory of memory, as proposed by F. I. Craik and R. S. Lockhart (see record 1973-20189-001). In Study 1, 20 hypnotized Ss (high hypnotizables), relaxed/motivated Ss (high hypnotizables), and 20 simulating Ss (low hypnotizables) processed lists of words matched for meaningfulness and imagery value at "deep" or "shallow" levels. As predicted, the hypnotized group recalled more deeply but not more shallowly processed stimuli than the control groups. In Study 2, these findings were replicated with 30 undergraduates using improved experimental procedures and were extended to a recognition situation. In neither study was the observed hypnotic enhancement accompanied by an increment in errors. It is concluded that cognition at the time of processing is critical in rendering a stimulus amenable to hypnotic hypermnesia. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Case Study: Channel Stability of the Missouri River, Eastern Montana

The construction of Fort Peck Dam in the 1930s on the Missouri River, eastern Montana, initiated a series of changes in hydrologic conditions and channel morphology downstream from the dam that impacted channel stability. Impacts included streambed degradation of up to 3.6 m and substantially altered magnitude, frequency, and temporal distribution of flows. To investigate the effects of the altered flow regime and bed degradation on bank stability, two independent bank-stability analyses (one for planar failures, the other for rotational failures) were performed on 17 outside meanders. Both included the effects of matric suction and positive pore-water pressures, confining pressures, and layering. Instability occurred from the loss of matric suction and the generation of positive pore-water pressures. In this semiarid region, such hydrologic conditions are most likely to occur from the maintenance of moderate and high flows (greater than 425–566 m3/s) for extended periods (5–10 days or more), thereby providing a mechanism for saturation of the streambank. For the postdam period, average annual frequencies of flows maintained above 566 m3/s for 5- and 10-day durations are 149 and 257% greater, respectively. The analyses indicated that 30% of the sites were susceptible to planar failures while 53% of the sites were susceptible to rotational failures under sustained moderate- and high-flow conditions, while under a worst-case rapid drawdown scenario, 80% of the banks were susceptible to failure. Despite the negative effects of the altered flow regime, analysis of maps and aerial photographs shows that closure of Fort Peck Dam has resulted in a fourfold reduction of the average rate of long-term channel migration between the dam and the North Dakota border.     

Amniotic fluid alpha-fetoprotein determination at the time of genetic amniocentesis: has it outlived its usefulness?

The purpose of this retrospective study was to evaluate the utility of routine measurement of amniotic fluid alpha-fetoprotein levels at the time of second trimester genetic amniocentesis (mean gestational age, 17.3 weeks +/- 2.5 weeks standard deviation; median, 16.8 weeks; range, 15 to 22 weeks). During the study period 7174 patients underwent second trimester genetic amniocentesis. Outcome data were available in all cases. In 79 (1.1%) cases the amniotic fluid alpha-fetoprotein level was > or = 2.0 multiples of the median. Thirty-three of the 79 (42%) patients had normal ultrasonograms, and in 31 of 33 (94%) the amniotic fluid alpha-fetoprotein level was between 2.0 and 3.0 multiples of the median. Forty-six of the 79 (58%) patients had abnormal ultrasonographic findings, and of these, 82% were neural tube defects, abdominal wall defects, or cystic hygromas. Acetylcholinesterase was positive in 37 cases, all of which had abnormal ultrasonographic findings. None of the fetuses with negative findings on sonographic screening had detectable abnormalities at birth. In this study, with over 7000 patients, amniotic fluid alpha-fetoprotein and acetylcholinesterase levels did not increase the detection of fetal abnormalities. On the basis of these results, routine measurement of amniotic fluid alpha-fetoprotein level at the time of routine genetic amniocentesis (15 to 22 weeks) does not appear justified.     

Reactivity to ecological momentary assessment: An example using undergraduate problem drinkers.

A. A. Stone and S. Shiffman (1994) defined ecological momentary assessment (EMA) as monitoring or sampling strategies that assess phenomena at the moment they occur in natural settings, thus maximi7ing ecological validity while avoiding retrospective recall. To address the extent to which EMA affects the behavior and cognitions under observation, the authors examined behavioral and motivational reactivity to EMA among male and female undergraduate problem drinkers (n = 33). Participants completed a 2-week monitoring protocol using palmtop computers as well as pre- and postmonitoring measures of their drinking behavior and motivation for change. The findings suggest that the magnitude of reactivity to EMA is small. Suggestions for future research Are presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design for Stream Restoration

Stream restoration, or more properly rehabilitation, is the return of a degraded stream ecosystem to a close approximation of its remaining natural potential. Many types of practices (dam removal, levee breaching, modified flow control, vegetative methods for streambank erosion control, etc.) are useful, but this paper focuses on channel reconstruction. A tension exists between restoring natural fluvial processes and ensuring stability of the completed project. Sedimentation analyses are a key aspect of design since many projects fail due to erosion or sedimentation. Existing design approaches range from relatively simple ones based on stream classification and regional hydraulic geometry relations to more complex two- and three-dimensional numerical models. Herein an intermediate approach featuring application of hydraulic engineering tools for assessment of watershed geomorphology, channel-forming discharge analysis, and hydraulic analysis in the form of one-dimensional flow and sediment transport computations is described.     

Perceptual identification of contextual attributes and infant memory retrieval.

The contribution of specific contextual attributes to recognition of a well-learned cue was examined in 4 experiments with 6-mo-olds. 24 hrs after learning to move a given mobile in a distinctive visual surround by kicking, recognition of the training cue was tested in either the original context or in one in which only a single contextual attribute was altered. Retrieval was completely disrupted by all form changes involving the deletion of angles and by a chromatic figure/ground reversal, but a discriminable change in form color had no effect. Although infants displayed partial retention in a degraded context after 1 day, they displayed no retention when a reminder was administered in the same degraded context after 20 days. These data reveal that infants do not encode contextual information holistically; moreover, they imply a privileged status for highly specific information about the incidental setting in which an event occurs. Unless this same highly specific information is perceptually identified at the time of testing, the memory of that event will not be retrieved. Data are consistent with the hypothesis that the visual context serves as an initial attention gate for memory retrieval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)