Sediment pH and Redox Potential Affect the Bioavailability of Al, Cu, Fe, Mn, and Zn to Rooted Aquatic Macrophytes

1993 ◽  
Vol 50 (1) ◽  
pp. 143-148 ◽  
Author(s):  
Leland J. Jackson ◽  
Jacob Kalff ◽  
Joseph B. Rasnnussen

We have evaluated the role of sediment pH (4.7–7.1) and redox potential (88–305 mV) in determining the bioavailability of five metals to four species of isoetoid macrophytes. The four species (Eleocharis acicularis, Eriocaulon septangulare With., Isoetes sp., and Sagittaria graminae) did not differ significantly in the relationship between the contents of metals in plants and sediment. When data for all species were pooled, 28–80% of the variation in the log of plant metal content was explained by the log of sediment metal (Al, Fe, and Mn) or by the log of sediment organic content (Cu and Zn). Sediment pH explained 45% (Al), 10% (Cu), 20% (Fe), 5% (Mn), and 12% (Zn) variation over and above that explained by the sediment metal content. These results demonstrate that lower sediment pH, in the presence of mildly oxic redox conditions, increases the bioavailability of these five trace metals to rooted aquatic plants. Rooted macrophytes subject to acidification contain higher metal concentrations which may be transferred by grazing to higher trophic levels.

1985 ◽  
Vol 63 (12) ◽  
pp. 2468-2469 ◽  
Author(s):  
Scott D. Wilson

This study used field experiments to test whether insectivory confers any benefit on Drosera intermedia Hayne growing on lakeshores characterized by high sediment organic content and dense vegetation. Ramets were grown in pots containing organic shoreline sediment for one summer at Axe Lake, Ontario. Insect availability was controlled by nylon mesh. Biomass accumulated by D. intermedia was not affected by insect availability. In a second experiment, when D. intermedia was grown with ramets of Lysimachia terrestris (L.) BSP., the exclusion of insects significantly reduced the biomass accumulated by D. intermedia. These results suggest that insectivory may be important in reducing the effect of interspecific competition on D. intermedia growing in nutrient-rich habitats.


2020 ◽  
Vol 20 (14) ◽  
pp. 1341-1356
Author(s):  
Karel Nesměrák

Many biochemical reactions are based on redox reactions. Therefore, the redox potential of a chemical compound may be related to its therapeutic or physiological effects. The study of redox properties of compounds is a domain of electrochemistry. The subject of this review is the relationship between electrochemistry and medicinal chemistry, with a focus on quantifying these relationships. A summary of the relevant achievements in the correlation between redox potential and structure, therapeutic activity, resp., is presented. The first part of the review examines the applicability of QSPR for the prediction of redox properties of medically important compounds. The second part brings the exhaustive review of publications using redox potential as a molecular descriptor in QSAR of biological activity. Despite the complexity of medicinal chemistry and biological reactions, it is possible to employ redox potential in QSAR/QSPR. In many cases, this electrochemical parameter plays an essential but rarely absolute role.


2020 ◽  
Vol 43 ◽  
Author(s):  
Thomas Parr

Abstract This commentary focuses upon the relationship between two themes in the target article: the ways in which a Markov blanket may be defined and the role of precision and salience in mediating the interactions between what is internal and external to a system. These each rest upon the different perspectives we might take while “choosing” a Markov blanket.


Crisis ◽  
2016 ◽  
Vol 37 (3) ◽  
pp. 212-217 ◽  
Author(s):  
Thomas E. Joiner ◽  
Melanie A. Hom ◽  
Megan L. Rogers ◽  
Carol Chu ◽  
Ian H. Stanley ◽  
...  

Abstract. Background: Lowered eye blink rate may be a clinically useful indicator of acute, imminent, and severe suicide risk. Diminished eye blink rates are often seen among individuals engaged in heightened concentration on a specific task that requires careful planning and attention. Indeed, overcoming one’s biological instinct for survival through suicide necessitates premeditation and concentration; thus, a diminished eye blink rate may signal imminent suicidality. Aims: This article aims to spur research and clinical inquiry into the role of eye blinks as an indicator of acute suicide risk. Method: Literature relevant to the potential connection between eye blink rate and suicidality was reviewed and synthesized. Results: Anecdotal, cognitive, neurological, and conceptual support for the relationship between decreased blink rate and suicide risk is outlined. Conclusion: Given that eye blinks are a highly observable behavior, the potential clinical utility of using eye blink rate as a marker of suicide risk is immense. Research is warranted to explore the association between eye blink rate and acute suicide risk.


2015 ◽  
Vol 36 (3) ◽  
pp. 170-176 ◽  
Author(s):  
Erin N. Stevens ◽  
Joseph R. Bardeen ◽  
Kyle W. Murdock

Parenting behaviors – specifically behaviors characterized by high control, intrusiveness, rejection, and overprotection – and effortful control have each been implicated in the development of anxiety pathology. However, little research has examined the protective role of effortful control in the relation between parenting and anxiety symptoms, specifically among adults. Thus, we sought to explore the unique and interactive effects of parenting and effortful control on anxiety among adults (N = 162). Results suggest that effortful control uniquely contributes to anxiety symptoms above and beyond that of any parenting behavior. Furthermore, effortful control acted as a moderator of the relationship between parental overprotection and anxiety, such that overprotection is associated with anxiety only in individuals with lower levels of effortful control. Implications for potential prevention and intervention efforts which specifically target effortful control are discussed. These findings underscore the importance of considering individual differences in self-regulatory abilities when examining associations between putative early-life risk factors, such as parenting, and anxiety symptoms.


2016 ◽  
Vol 37 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Nicole L. Hofman ◽  
Austin M. Hahn ◽  
Christine K. Tirabassi ◽  
Raluca M. Gaher

Abstract. Exposure to traumatic events and the associated risk of developing Posttraumatic stress disorder (PTSD) symptoms is a significant and overlooked concern in the college population. It is important for current research to identify potential protective factors associated with the development and maintenance of PTSD symptoms unique to this population. Emotional intelligence and perceived social support are two identified protective factors that influence the association between exposure to traumatic events and PTSD symptomology. The current study examined the mediating role of social support in the relationship between emotional intelligence and PTSD symptoms. Participants included 443 trauma-exposed university students who completed online questionnaires. The results of this study indicated that social support mediates the relationship between emotional intelligence and reported PTSD symptoms. Thus, emotional intelligence is significantly associated with PTSD symptoms and social support may play an integral role in the relationship between emotional intelligence and PTSD. The current study is the first to investigate the role of social support in the relationship between emotional intelligence and PTSD symptoms. These findings have important treatment and prevention implications with regard to PTSD.


2017 ◽  
Vol 16 (3) ◽  
pp. 155-159 ◽  
Author(s):  
Peizhen Sun ◽  
Jennifer J. Chen ◽  
Hongyan Jiang

Abstract. This study investigated the mediating role of coping humor in the relationship between emotional intelligence (EI) and job satisfaction. Participants were 398 primary school teachers in China, who completed the Wong Law Emotional Intelligence Scale, Coping Humor Scale, and Overall Job Satisfaction Scale. Results showed that coping humor was a significant mediator between EI and job satisfaction. A further examination revealed, however, that coping humor only mediated two sub-dimensions of EI (use of emotion and regulation of emotion) and job satisfaction. Implications for future research and limitations of the study are discussed.


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