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One focus of 21st century science education is teaching students authentic disciplinary practices. Scientific argumentation is one such practice, and evidence suggests it is not only a key skill, but also a facilitator of high-level comprehension. Science teachers need assistance teaching and incorporating argumentation into their work. In this study, we implemented Quality Talk, a small-group discourse model shown to foster argumentation and conceptual understanding, in four high school science classrooms. Using a quasi-experimental design, we found Quality Talk students, compared to control group students, displayed better verbal and written argumentation. Conceptual understanding performance did not differ by group, but post hoc analyses suggested new directions for improving Quality Talk and other methods of fostering scientific argumentation and understanding.

Antimicrobial peptides are found in all organisms and have gained notoriety in recent years for their effectiveness against a variety of pathogens. Piscidins, first isolated from the mast cells of vertebrates, comprise a family of these host defense peptides. Piscidins 1 (P1) and 3 (P3), found in sea bass and other fishes, are isoforms with different modes of action. P1 induces membrane perturbation, while P3 binds DNA to exert antibacterial activity. Each has the ability to bind Cu2+ (P1Cu and P3Cu) which dramatically impacts their antimicrobial characteristics. The purpose of this study was to investigate the activity of metallated and nonmetallated P1 and P3 on Vibrio cholerae, a Gram-negative bacterium of medical importance that normally inhabits an aquatic environment, often associating with fish and other marine life. Known to assimilate exogenous fatty acids into membrane phospholipids, V. cholerae possesses the ability to modify membrane permeability depending upon environmental fatty acid availability. Herein we investigated both permeability and antimicrobial effects of P1, P1Cu, P3, and P3Cu on V. cholerae grown in the presence and absence of linoleic acid (18:2). Membrane permeability was assessed using a crystal violet assay. These experiments observed a marked decrease (~15%) in permeability when the bacteria is provided 18:2. All piscidins elicited heightened permeability, with 18:2 decreasing the effect for nonmetallated forms of the peptide. Furthermore, some piscidins displayed concentration dependence with regard to permeability effects. The minimum inhibitory concentrations (MICs) for P1 and P1Cu were increased 2-fold when 18:2 was supplemented. The MIC of P3 was significantly decreased (4-fold) in the presence of 18:2, while no difference was observed with P3Cu. Not only do piscidins alter bacterial membrane permeability and display promising antimicrobial capabilities, but the observed effects of exogenous fatty acid supplementation could also hold potential for targeted treatment of infectious disease. [ABSTRACT FROM AUTHOR]

Despite perceptions that infidelity is common in the military, there is relatively little evidence documenting the prevalence of extramarital sex among active-duty service members or veterans. Using data from the 1992 National Health and Social Life Survey, we estimate multivariate logistic regression models to examine the association between veteran status and extramarital sex, and the association between veteran status and divorce, among ever-married persons aged 18-60 years. We examine whether the association between veteran status and divorce is accounted for by extramarital sex, and whether veteran status moderates the association between extramarital sex and divorce. We also conduct supplemental analyses of sex (gender) differences. We find that 32.17% of veterans report extramarital sexual relationships, which is twice the rate among non-veterans. Controlling for sociodemographic and early-life factors, veterans are significantly more likely than non-veterans to report extramarital sex and to have ever divorced, and this latter association is fully explained by veterans' higher odds of marital infidelity. We find no evidence that the association between extramarital sex and divorce is moderated by veteran status. We conclude that veteran status is strongly associated with extramarital sex and divorce, at least among men; extramarital sex and divorce might also be elevated among female veterans, but research that uses larger, representative samples of female veterans is needed to confirm those associations. This research can inform a conceptual framework for understanding how military service and deployment influence service members, couples, and families. It can also inform the development of interventions used with military families. [ABSTRACT FROM AUTHOR]