Investigating CSI: portrayals of DNA testing on a forensic crime show and their potential effects

The popularity of forensic crime shows such as CSI has fueled debate about their potential social impact. This study considers CSI's potential effects on public understandings regarding DNA testing in the context of judicial processes, the policy debates surrounding crime laboratory procedures, and the forensic science profession, as well as an effect not discussed in previous accounts: namely, the show's potential impact on public understandings of DNA and genetics more generally. To develop a theoretical foundation for research on the "CSI effect," it draws on cultivation theory, social cognitive theory, and audience reception studies. It then uses content analysis and textual analysis to illuminate how the show depicts DNA testing. The results demonstrate that CSI tends to depict DNA testing as routine, swift, useful, and reliable and that it echoes broader discourses about genetics. At times, however, the show suggests more complex ways of thinking about DNA testing and genetics.     

Cross-lagged relationships among leisure-time exercise and perceived stress in blue-collar workers

Blue-collar workers (N = 203) from a large food-processing plant in the southwestern U.S. completed measures of perceived stress and leisure-time exercise at an initial test session in addition to a 2-month follow-up session. Mean age of the sample participants equaled 43.61 (SD = 9.79), and 69.5% of the sample were male, 71.4% were Caucasian, and 74.9% were married/cohabitating. Structural equation modeling was employed to examine the cross-lagged relationships between perceived stress and leisure-time exercise at these time points, controlling for gender, marital status, age, and yearly household income. Results indicated that a model with a path from perceptions of Time 1 stress to Time 2 exercise frequency was most parsimonious and provided acceptable model fit, suggesting that perceptions of stress are related to reductions in exercise participation in this population. However, there was little support for a relationship between Time 1 exercise participation and Time 2 perceived stress.     

Influence of cold-water immersion on indices of muscle damage following prolonged intermittent shuttle running

Abstract

The aim of this study was to assess the effects of cold-water immersion (cryotherapy) on indices of muscle damage following a bout of prolonged intermittent exercise. Twenty males (mean age 22.3 years, s = 3.3; height 1.80 m, s = 0.05; body mass 83.7 kg, s = 11.9) completed a 90-min intermittent shuttle run previously shown to result in marked muscle damage and soreness. After exercise, participants were randomly assigned to either 10 min cold-water immersion (mean 10°C, s = 0.5) or a non-immersion control group. Ratings of perceived soreness, changes in muscular function and efflux of intracellular proteins were monitored before exercise, during treatment, and at regular intervals up to 7 days post-exercise. Exercise resulted in severe muscle soreness, temporary muscular dysfunction, and elevated serum markers of muscle damage, all peaking within 48 h after exercise. Cryotherapy administered immediately after exercise reduced muscle soreness at 1, 24, and 48 h (P < 0.05). Decrements in isometric maximal voluntary contraction of the knee flexors were reduced after cryotherapy treatment at 24 (mean 12%, s _x  = 4) and 48 h (mean 3%, s _x  = 3) compared with the control group (mean 21%, s _x  = 5 and mean 14%, s _x  = 5 respectively; P < 0.05). Exercise-induced increases in serum myoglobin concentration and creatine kinase activity peaked at 1 and 24 h, respectively (P < 0.05). Cryotherapy had no effect on the creatine kinase response, but reduced myoglobin 1 h after exercise (P < 0.05). The results suggest that cold-water immersion immediately after prolonged intermittent shuttle running reduces some indices of exercise-induced muscle damage.     

Replacement of event-generated memories of nonreinforcement with signal-generated memories of reinforcement during partial reinforcement training: Effect on resistance to extinction

Event-generated memory refers to the memory of a reinforcement (R) or nonreinforcement (N) event from an immediately preceding trial;signal-generated memory refers to the memory of a temporally remote R or N, retrieval of which is generated by presentation of a signal with which the memory is associated (Haggbloom, 1988). In each of three experiments, Group Signal-R received runway discrimination training in Phase 1 to establish a stimulus as a signal for R, and partial reinforcement training in Phase 2. An extinction test measured learning about the memory of nonreward (S^N)—learning that occurs when S^N is retrieved on R trials that follow N trials. In Group Signal-H, those R trials were accompanied by the signal for R, a treatment we hypothesized would generate retrieval of the memory of reinforcement (S^R) so that signal-generated S^R would replace event-generated S^N as the operative memory, thereby eliminating the increased resistance to extinction normally produced by PRF training. In each experiment, Group Signal-R was less resistant to extinction than was a control group conditioned to respond to-event-generated S^N. Extinction was as rapid in Group Signal-R as it was in a consistent reinforcement control group (Experiment 1) and in a group given intertrial reinforcements to interfere with learning about S^N (Experiment 3). Experiment 2 tested two alternative interpretations of the failure to learn about S^N in Group Signal-R. Those alternatives were found to be less viable than the hypothesis that the signal for R actively recruited retrieval of a competing memory.     

Recreating blood-brain barrier physiology and structure on chip: A novel neurovascular microfluidic bioreactor

The blood-brain barrier (BBB) is a critical structure that serves as the gatekeeper between the central nervous system and the rest of the body. It is the responsibility of the BBB to facilitate the entry of required nutrients into the brain and to exclude potentially harmful compounds; however, this complex structure has remained difficult to model faithfully in vitro. Accurate in vitro models are necessary for understanding how the BBB forms and functions, as well as for evaluating drug and toxin penetration across the barrier. Many previous models have failed to support all the cell types involved in the BBB formation and/or lacked the flow-created shear forces needed for mature tight junction formation. To address these issues and to help establish a more faithful in vitro model of the BBB, we have designed and fabricated a microfluidic device that is comprised of both a vascular chamber and a brain chamber separated by a porous membrane. This design allows for cell-to-cell communication between endothelial cells, astrocytes, and pericytes and independent perfusion of both compartments separated by the membrane. This NeuroVascular Unit (NVU) represents approximately one-millionth of the human brain, and hence, has sufficient cell mass to support a breadth of analytical measurements. The NVU has been validated with both fluorescein isothiocyanate (FITC)-dextran diffusion and transendothelial electrical resistance. The NVU has enabled in vitro modeling of the BBB using all human cell types and sampling effluent from both sides of the barrier.     

An empirical test of a taxonomy of responses to anomalous data in science

The purpose of this study was to test a taxonomy of seven proposed responses to anomalous data. Our results generally supported the taxonomy but indicated that one additional type of response should be added to the taxonomy. We conclude that there are eight possible responses to anomalous data: (a) ignoring the data, (b) rejecting the data, (c) professing uncertainty about the validity of the data, (d) excluding the data from the domain of the current theory, (e) holding the data in abeyance, (f) reinterpreting the data, (g) accepting the data and making peripheral changes to the current theory, and (h) accepting the data and changing theories. We suggest that this taxonomy could help science teachers in two ways. First, science teachers could use the taxonomy to try to anticipate how students might react to anomalous data so as to make theory change more likely. Second, science teachers could use the taxonomy as a framework to guide classroom discussion about the nature of scientific rationality. In addition, the taxonomy suggests directions for future research. © 1998 John Wiley & Sons, Inc. J Res Sci Teach 35: 623–654, 1998.