Metal ion sorption by chitosan–tripolyphosphate beads

Heavy metal removal from wastewater is crucial for the proper management of discharged water from mining operations. This residual water is typically unusable for other purposes such as for human/animal, crop, or industrial consumption. Eco‐friendly adsorption materials are necessary to ensure the sustainable treatment of this wastewater. Therefore, the sorption of Cu(II), Cd(II), Pb(II), and Zn(II) ions onto chitosan–tripolyphosphate (CTPP) beads was investigated using real mining wastewater and prepared ion metal solutions. The effects of pH, contact time, temperature, selectivity, and maximum sorption capacity in successive batches at different concentrations were studied. The optimum sorption of cations, except for copper (pH 3) was found at pH 5. Equilibrium in the adsorption of all metals was reached at 24 h of contact. Studies of the maximum sorption capacity at different concentrations showed that the CTPP beads could adsorb 158, 55, 47, and 47 mg/g of Pb(II), Cu(II), Cd(II), and Zn(II), respectively. Experimental data for the sorption of Pb(II) were optimally correlated with the Langmuir model. The thermodynamic parameters such as the changes in enthalpy (ΔH⁰), entropy (ΔS⁰), and free energy (ΔG⁰) were determined. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45511.     

Carnivore Attractant or Plant Elicitor? Multifunctional Roles of Methyl Salicylate Lures in Tomato Defense

Synthetic plant volatile lures attract natural enemies, but may have non-target effects due to the multifunctional nature of volatile signals. For example, methyl salicylate (MeSA) is used to attract predators, yet also serves as a signaling hormone involved in plant pathogen defense. We investigated the consequences of deploying MeSA lures to attract predators for tomato (Solanum lycopersicum) defense against herbivores. To understand the spatial distribution of the lure’s effect, we exposed tomatoes in the field to MeSA along a linear distance gradient and induced defenses by simulating feeding by hornworm caterpillars in a fully crossed factorial design (+/? MeSA, +/? herbivory). Subsequently, we analyzed activity of several defensive proteins (protease inhibitors, polyphenol oxidase, peroxidase), development of hornworm larvae (Manduca sexta), growth of fungal pathogens (Cladosporium and Alternaria), and attractiveness to herbivores and predators. Overall, MeSA-exposed plants were more resistant to both insects and pathogens. Secondary pathogen infection was reduced by 25% in MeSA exposed plants, possibly due to elevated polyphenol oxidase activity. Interestingly, we found that lures affected plant pathogen defenses equivalently across all distances (up to 4 m away) indicating that horizontal diffusion of a synthetic volatile may be greater than previously assumed. While thrips avoided colonizing hornworm– damaged tomato plants, this induced resistance was not observed upon pre-exposure to MeSA, suggesting that MeSA suppresses the repellant effect induced by herbivory. Thus, using MeSA lures in biological control may inadvertently protect crops from pathogens, but has mixed effects on plant resistance to insect herbivores.     

Accumulation of eicosapentaenoic acid in plasma phospholipids of subjects fed canola oil

The metabolism of α-linolenic acid from canola oil was studied in eight normolipidemic men. The 42-day study was divided into three periods: a 6-day pre-experimental and two 18-day experimental. Approximately 75% of the dietary fat (28% of total energy) was provided by a mixture of fats during the pre-experimental period and either canola oil (CO) or sunflower oil (SO) during the experimental periods. The CO and SO diets were fed in a cross-over design. The ratios of linoleic to linolenic acid were 2.6∶1 and 73.9∶1 in the CO and SO diets, respectively. Dietary fat source had an effect on plasma phospholipid fatty acids: 18∶1n−9, 18∶3n−3 and 20∶5n−3 were higher (p<0.05), and 18∶2n−6 was lower in the phosphatidylcholine fraction; 18∶1n−9 was higher and 20∶4n−6 lower in the phosphatidyl-ethanolamine fraction; and 18∶1n−9 and 20∶5n−3 were higher and 20∶4n−6 and 22∶6n−3 were lower in the alkenylacyl-ethanolamine phospholipid fraction on the CO diet as compared to the SO diet. Consumption of the canola oil diet resulted in higher n−3 fatty acid levels and lower n−6 fatty acid levels in plasma phospholipids than consumption of the sunflower oil diet.     

35 years and 160,000 articles: A bibliometric exploration of the evolution of ecology

We utilize the bibliometric tool of co-word analysis to identify trends in the methods and subjects of ecology during the period 1970–2005. Few previous co-word analyses have attempted to analyze fields as large as ecology. We utilize a method of isolating concepts and methods in large datasets that undergo the most significant upward and downward trends. Our analysis identifies policy-relevant trends in the field of ecology, a discipline that helps to identify and frame many contemporary policy problems. The results provide a new foundation for exploring the relations among public policies, technological change, and the evolution of science priorities.     

Is a sense of inequity an ancestral primate trait? Testing social inequity in cotton top tamarins (Saguinus oedipus).

To address a controversy in the literature concerning whether monkeys show an aversion to inequity, individuals of a New World monkey species, cotton top tamarins (Saguinus oedipus) were tested in an offering task and in a bartering task. At issue was whether the monkeys rejected rewards because of a violation of expectancy of the preferred reward, or whether they rejected rewards because of a sensitivity to socially mediated inequity. The data from both tasks indicated that the subjects were more likely to reject when preferred rewards were presented, either because of another animal eating the reward (the social condition) or because of rewards being presented but inaccessible. The bartering task led to the only behavioral indication of aversion due specifically to social inequity, which was demonstrated when tamarins' sensitivity to the difference in rewards increased with exposure to other tamarins working to receive the preferred rewards. The results suggest that social inequity aversion will be assessed by tamarins, and possibly by other primates, only under conditions of limited resources and a requirement of work, which may make the situation a bit more competitive and thus drives attention toward both social and reward evaluation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What's in a norm? Sources and processes of norm change.

This reply to the commentary by E. Staub and L. A. Pearlman (2009) revisits the field experimental results of E. L. Paluck (2009). It introduces further evidence and theoretical elaboration supporting Paluck's conclusion that exposure to a reconciliation-themed radio soap opera changed perceptions of social norms and behaviors, not beliefs. Experimental and longitudinal survey evidence reinforces the finding that the radio program affected socially shared perceptions of typical or prescribed behavior—that is, social norms. Specifically, measurements of perceptions of social norms called into question by Staub and Pearlman are shown to correlate with perceptions of public opinion and public, not private, behaviors. Although measurement issues and the mechanisms of the radio program's influence merit further testing, theory and evidence point to social interactions and emotional engagement, not individual education, as the likely mechanisms of change. The present exchange makes salient what is at stake in this debate: a model of change based on learning and personal beliefs versus a model based on group influence and social norms. These theoretical models recommend very different strategies for prejudice and conflict reduction. Future field experiments should attempt to adjudicate between these models by testing relevant policies in real-world settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neural basis for recognition confidence in younger and older adults.

Although several studies have examined the neural basis for age-related changes in objective memory performance, less is known about how the process of memory monitoring changes with aging. The authors used functional magnetic resonance imaging to examine retrospective confidence in memory performance in aging. During low confidence, both younger and older adults showed behavioral evidence that they were guessing during recognition and that they were aware they were guessing when making confidence judgments. Similarly, both younger and older adults showed increased neural activity during low- compared to high-confidence responses in the lateral prefrontal cortex, anterior cingulate cortex, and left intraparietal sulcus. In contrast, older adults showed more high-confidence errors than younger adults. Younger adults showed greater activity for high compared to low confidence in medial temporal lobe structures, but older adults did not show this pattern. Taken together, these findings may suggest that impairments in the confidence–accuracy relationship for memory in older adults, which are often driven by high-confidence errors, may be primarily related to altered neural signals associated with greater activity for high-confidence responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enhanced maternal aggression and associated changes in neuropeptide gene expression in multiparous rats.

Although it has often been speculated that prior reproductive experience improves subsequent maternal care, few studies have examined specific changes in behavior during a 1st versus 2nd lactation. During lactation, mothers display heightened aggression toward male intruders, purportedly to protect vulnerable young. In the current study, maternal aggression was examined in primiparous and age-matched multiparous females on postpartum days 5 (PPD5) and PPD15. Expression of oxytocin, oxytocin receptor, arginine vasopressin, arginine vasopressin V1a receptors, and corticotrophin-releasing hormone mRNA was measured following aggression testing at both time points using real-time quantitative PCR in brain regions previously implicated in the regulation of maternal aggression. Multiparity significantly enhanced maternal aggression on PPD5 but not on PPD15. In addition, this increased aggression was associated with region- and gene-specific changes in mRNA expression. These findings indicate that reproductive experience enhances maternal aggression, an effect that may be mediated by region-specific alterations in neuropeptidergic activity. The adaptations observed in multiparous females provide an innate model for the study of neuroplasticity in the regulation of aggression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceived discrimination and health: A meta-analytic review.

Perceived discrimination has been studied with regard to its impact on several types of health effects. This meta-analysis provides a comprehensive account of the relationships between multiple forms of perceived discrimination and both mental and physical health outcomes. In addition, this meta-analysis examines potential mechanisms by which perceiving discrimination may affect health, including through psychological and physiological stress responses and health behaviors. Analysis of 134 samples suggests that when weighting each study’s contribution by sample size, perceived discrimination has a significant negative effect on both mental and physical health. Perceived discrimination also produces significantly heightened stress responses and is related to participation in unhealthy and nonparticipation in healthy behaviors. These findings suggest potential pathways linking perceived discrimination to negative health outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)