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Biomedical subjects

B Wallace

Publications and source records attributed to B Wallace.

At least 37 records · Page 2Linked to original sources
PubMed1995

Severe acidosis alone does not predict mortality in the trauma patient.

BACKGROUND: Because severe acidosis is an indicator of poor prognosis in trauma patients, medical records of these patients were analyzed to determine whether aggressive resuscitation was appropriate. PATIENTS AND METHODS: Data from a level 1 trauma center registry were reviewed retrospectively to identify patients with a pH < or = 7.0. Thirty-seven patients were identified. Severely acidotic patients were compared to average trauma patients in terms of demographics, resuscitation, injury, and outcome. Surviving acidotic patients were also compared to nonsurviving acidotic patients. RESULTS: Half of the severely acidotic group survived initial resuscitation with approximately one third surviving to leave the hospital. There were no chronically disabled survivors. Nonsurviving acidotic patients were more unstable, more neurologically depressed, and more severely injured. Resuscitation efforts did not consume excessive hospital resources. CONCLUSION: Severe acidosis alone is not a sufficiently powerful predictor of outcome to justify withholding resuscitation; however, when combined with coma and shock, this condition had no survivors in this small series.

Acidosis↗
PubMed1995

Influence of case type, word frequency, and exposure duration on visual word recognition.

The authors report 4 lexical decision experiments in which case type, word frequency, and exposure duration were varied. These data indicated that there is a larger mixed-case disadvantage for nonwords than for words for longer duration presentations of targets. However, when targets were presented for 100 ms (followed by a postdisplay pattern mask), a larger mixed-case disadvantage occurred for words than for nonwords. For word frequency, the data from Experiments 1, 2, and 3 revealed a slightly larger mixed- case disadvantage for higher frequency words than for lower frequency words. (There was additivity between word frequency and case type for experiment 4.) These results are consistent with a holistically biased, hybrid model of visual word recognition but inconsistent with analytically biased, hybrid models of word recognition, such as the process model (Besner & Johnston, 1989) and the interactive-activation model (McClelland & Rumelhart, 1981).

Decision Making↗
PubMed1995

Fluctuations in hypnotic susceptibility and imaging ability over a 16-hour period.

Within-subject variability for hypnotic susceptibility as measured by the Harvard Group Scale of Hypnotic Susceptibility, Form A and for imaging ability as measured by the Vividness of Visual Imagery Questionnaire was determined over a 16-hour period. Half of the subjects were day persons, those most alert during daytime hours (as determined by the Alertness Questionnaire); the remaining subjects were night persons. For day persons, hypnotic susceptibility was greatest at 10:00 a.m. and 2:00 p.m.; for night persons, susceptibility was greatest at 1:00 p.m. and between 6:00 p.m. and 9:00 p.m. Imaging ability also varied as a function of time of administration. However, these peak periods occurred before and after hypnotic susceptibility peaks. Such a pattern was interpreted as indicating the possible existence of an ultradian cycle for imaging ability.

Activity Cycles↗
PubMed1994

Norms of reaction and diversifying selection.

The numbers of progeny produced by comparable numbers of female Drosophila melanogaster of 26 geographic strains on nine different culture media are examined in the context of norms of reaction. Having emphasized that diversifying selection is seldom discussed simultaneously with its seemingly related topic, norms of reaction, I present the following argument: diversifying selection has generally been viewed as involving sub-populations inhabiting separate localities and subject to different patterns of selection, norms of reaction as variation whose weighted average determines the relative fitnesses of different genotypes within individual sub-populations. Should environmental challenges frequently involve life or death (including sterility) outcomes, norms of reaction involving components of fitness engender diversifying selection within local populations (demes).

Animals↗
PubMed1994

Hypnotic susceptibility, imaging ability, and the detection of embedded words within letters.

Two experiments were conducted to determine the role of hypnotic susceptibility level (high or low) and imaging ability (vivid or poor) in the performance of a visual search for words embedded within matrices of letters. In Experiment 1, subjects searched for target words from a list; however, distractor words were also embedded in the matrices. Results indicated that subjects judged both high in hypnotic susceptibility and vivid in imaging ability demonstrated the fastest search speed with a greater percentage of target words found. These subjects also made fewer false alarm errors (locating distractor words not on the target list). The poorest performance was exhibited by subjects judged both low in hypnotic susceptibility and poor in imaging ability. The amount of variance accounted for by hypnotic susceptibility and imaging ability was approximately equal for each dependent measure. In Experiment 2, when subjects searched for target words from a list without distractor words embedded in matrices, similar results to those reported for Experiment 1 were produced, except that the percentage of words found was equivalent across groups. This was attributed to the elimination of potential false alarm errors. The results are explained in terms of the use of either a holistic or a detail strategy in the performance of a visual search.

Adult↗
PubMed1994

Effects of movement duration and visual feedback on visual and proprioceptive components of prism adaptation.

While looking through laterally displacing prisms, subjects pointed sagittally 80 times at an objectively straight-ahead target, completing a reciprocal out-and-back pointing movement ever 1, 3, or 6 s. Visual feedback was available early in the pointing movement or only late at the end of the movement. Aftereffect measures of adaptive shift (obtained after every 10 pointing trials) showed adaptive change only in limb position sense (i.e., proprioceptive adaptation) when movement duration was 1 s, regardless of visual feedback condition; but as movement duration increased, adaptive change in the eye position sense (i.e., visual adaptation) increased while proprioceptive adaptation decreased, especially for the late visual feedback condition. Regardless of visual feedback condition, proprioceptive adaptation showed the maximal rate of growth with the 1-s movement duration, whereas visual adaptation showed maximal growth with the 6-s movement duration. These results provide additional support for a model of adaptive spatial mapping in which the direction of strategically flexible coordination (guidance) between eye and limb (and consequently the locus of adaptive spatial mapping) is jointly determined by movement duration and timing of visual feedback. An additional effect of movement duration is to determine the rate of discordant inputs. Maximal growth of adaptation occurs when the input rate matches the response time of the spatial mapping function.

Journal Article↗
PubMed1994

Influence of imaging ability on word transformation.

In the present study, we examined whether individual differences in imaging ability affect visual word recognition. Poor and vivid imagers performed a naming task that involved nonreversed (e.g., JUMP) and reversed (e.g., PMUJ) words (Experiment 1). Poor and vivid imagers were also tested on a naming task that was controlled for verbal ability; all the words were reversed and presentation time was varied (Experiment 2). In both experiments, imaging ability interacted with task difficulty, suggesting that individual differences in imaging ability affect visual word recognition. Specifically, the present data suggest that poor imagers may be less efficient than vivid imagers at processing words analytically. The data are interpreted within a limited-capacity, hybrid, word recognition model, in which words can be processed as either word-level or letter-level codes.

Adult↗
PubMed1993

Day persons, night persons, and variability in hypnotic susceptibility.

Day persons (those most alert during daytime hours) and night persons participated in 2 experiments to examine within-subject variability of scores over time on the Harvard Group Scale of Hypnotic Susceptibility, Form A, and the Stanford Hypnotic Susceptibility Scale, Form C. Regardless of scale used, day persons exhibited peak susceptibility at 10 a.m. and 2 p.m.; for night persons, peak susceptibility was found at 1 p.m. and between 6 p.m. and 9 p.m. Furthermore, 2 peaks of temperature increase (1 p.m. and 6 p.m.) appeared to be associated with peaks in hypnotic susceptibility. However, such was shown to be associated with periods of food intake rather than with increases in hypnotic susceptibility. Results are examined with respect to methodological concerns and the potential existence of ultradian rhythms for hypnotic responsiveness.

Adult↗
PubMed1993

Determinants of diagnostic hypothesis generation: effects of information, base rates, and experience.

Physicians generated diagnostic hypotheses for case histories for which 2 types of diagnoses were plausible, with one having a higher population base rate but less severe clinical consequences than the other. The number of clinical and background symptoms pointing towards the 2 diagnoses was factorially manipulated. The order and frequency with which physicians generated hypotheses varied with the amount of relevant clinical and background information and as a function of population incidence rates, with little evidence of base rate neglect. Availability of a hypothesis, made possible by diagnosis of a similar case before, also made doctors generate this diagnosis earlier and more frequently. Physicians' experience affected hypothesis generation solely by increasing the availability of similar cases. The results are consistent with the use of similarity-based hypothesis generation processes that operate on memory for prior cases.

Adult↗
PubMed1993

Working with shame in the group treatment of male batterers.

The authors argue that shame is a core issue for many men who assault their partners. Shame must therefore be addressed in treatment groups. This article outlines how one intervention, "the confession," elicits shame and how that shame is negotiated through the various stages of group development.

Anger↗
PubMed1993

Adaptive coordination and alignment of eye and hand.

Under spatial misalignment of eye and hand induced by laterally displacing prisms (11.4 degrees in the rightward direction), subjects pointed 60 times (once every 3 s) at a visually implicit target (straight ahead of nose, Experiment 1) or a visually explicit target (an objectively straight-ahead target, Experiment 2). For different groups in each experiment, the hand became visible early in the sagittal pointing movement (early visual feedback). Adaptation to the optical misalignment during exposure (direct effects) was rapid, especially with early feedback; complete compensation for the misalignment was achieved within about 30 trials, and overcompensation occurred in later trials, especially with an explicit target. In contrast, adaptation measured with the misalignment removed and without visual feedback after blocks of 10 pointing trials (aftereffects) was slow to develop, especially with delayed feedback and an implicit target; at most, about 40% compensation for the misalignment occurred after 60 trials. This difference between direct effects and aftereffects is discussed in terms of separable adaptive mechanisms that are activated by different error signals. Adaptive coordination is activated by error feedback and involves centrally located, strategically flexible, short-latency processes to correct for sudden changes in operational precision that normally occur with short-term changes in coordination tasks. Adaptive alignment is activated automatically by spatial discordance between misaligned systems and involves distributed, long-latency processes to correct for slowly developing shifts in alignment among perceptual-motor components that normally occur with long-term drift. The sudden onset of misalignment in experimental situations activates both mechanisms in a complex and not always cooperative manner, which may produce overcompensatory behavior during exposure (i.e., direct effects) and which may limit long-term alignment (i.e., aftereffects).

Journal Article↗
PubMed1992

Experience of peripheral temperature change during hypnotic analgesia.

Many Ss who experience hypnotic analgesia in a portion of their body often report that it is accompanied by sensations of coldness in the affected area. Experiments were conducted to determine if such reports are the result of a physical change in peripheral temperature or are due to psychological factors. When analgesia was induced in a limb or in the back of the neck, a concomitant physical change in temperature was not observed. Ss did report experiencing coldness, however, in the affected body part. Such experiences were attributed to associations that Ss developed between numbness or analgesia and a drop in peripheral temperature. As a result, coldness as an associate of hypnotic analgesia is suggested as a manipulation check for the presence of such sensation reduction.

Female↗
PubMed1992

Revised nucleotide sequence of the gltP gene, which encodes the proton-glutamate-aspartate transport protein of Escherichia coli K-12.

The gene encoding the proton-glutamate carrier (GltP) of Escherichia coli K-12 was sequenced, and the primary structure of the protein was analyzed. The nucleotide sequence was found to differ in several aspects from the previously published sequence (B. Wallace, Y. Yang, J. Hong, and D. Lum, J. Bacteriol. 172:3214-3220, 1990). The corrected open reading frame encodes a protein of 437 (instead of 395) amino acids. Hydropathy analysis predicts 12 membrane-spanning alpha-helical regions. The complementary strand does contain an open reading frame possibly encoding a highly hydrophilic polypeptide of 272 amino acids.

Amino Acid Sequence↗
PubMed1992

Process generalization and the prediction of performance on mental imagery tasks.

Kosslyn (1980, 1983) theorized that performance measures on imagery tasks may vary as a function of the existence of independent processes in imaging ability. The present study determined whether improvement can be made in performance on such tasks with practice. It also considered whether performance on such tasks improves with practice and whether this improvement generalizes. Experiment 1 determined whether improvement in a mental rotation task generalizes to improvement in a geometric analogies task, with both tasks weighted in Kosslyn's find process, but not in a line drawing memory task weighted in Kosslyn's regenerate process. In Experiment 2, we examined generalization in improvement from a geometric analogies task to a mental rotation task. In Experiment 3, we tested whether improvement in an animal imagery task (Kosslyn, 1975) generalizes to improvement in a line drawing memory task, with both tasks weighted in Kosslyn's regenerate process, but not to improvement in a mental rotation task. Performance improved with practice on all tasks. Furthermore, performance improved from one task to another only if both tasks loaded on the same process.

Adult↗
PubMed1992

Fearing to give life.

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Acquired Immunodeficiency Syndrome↗
PubMed1991

The manly art of self-defense: on the neutrality of fitness components.

Data on 15 physical characteristics of contenders in 137 championship prizefights in three weight categories (light-, middle-, and heavyweights) have been analysed. These data are seen as being drawn from a highly culled population, and as bearing on what are, in effect, components of fitness. In heavyweights, the analysis suggests that these characteristics are indeed related to winning or losing (i.e., they are selectively important). As an overwhelmingly general rule, however, winners and losers do not differ significantly with respect to these measures nor, for the lighter weight classes, is there evidence of stabilizing selection. The exceptions to this general rule are discussed ("just-so" story): under some circumstances, a correlation between total fitness and one of its components may be detected in a highly selected population. Under most circumstances, on the contrary, this correlation all but vanishes.

Boxing↗