scholarly journals Interactive effects of acidification, hypoxia, and thermal stress on growth, respiration, and survival of four North Atlantic bivalves

2018 ◽  
Vol 604 ◽  
pp. 143-161 ◽  
Author(s):  
AM Stevens ◽  
CJ Gobler
2020 ◽  
Vol 319 (6) ◽  
pp. R703-R711
Author(s):  
Alessandro Valenza ◽  
Harry Charlier ◽  
Antonino Bianco ◽  
Davide Filingeri

Many occupations and sports require high levels of manual dexterity under thermal stress and mental fatigue. Yet, multistressor studies remain scarce. We quantified the interactive effects of thermal stress and mental fatigue on manual dexterity. Seven males (21.1 ± 1.3 yr) underwent six separate 60-min trials characterized by a combination of three air temperatures (hot, 37°C; neutral, 21°C; cold, 7°C) and two mental fatigue states (MF, mental fatigue induced by a 35-min cognitive battery; no-MF, no mental fatigue). Participants performed complex (O’Connor test) and simple (hand-tool test) manual tasks pre- and posttrial to determine stressor-induced performance changes. We monitored participants’ rectal temperature and hand skin temperature (Thand) continuously and assessed the reaction time (hand-click test) and subjective mental fatigue (5-point scale). Thermal stress ( P < 0.0001), but not mental fatigue ( P = 0.290), modulated Thand (heat, +3.3°C [95% CI: +0.2, +6.5]; cold, −7.5°C [−10.7, −4.4]). Mental fatigue ( P = 0.021), but not thermal stress ( P = 0.646), slowed the reaction time (∼10%) and increased subjective fatigue. Thermal stress and mental fatigue had an interactive effect on the complex manual task ( P = 0.040), with cold-no-MF decreasing the performance by −22% [−39, −5], whereas neutral-MF, cold-MF, and heat-MF by −36% [−53, −19], −34% [−52, −17], and −36% [−53, −19], respectively. Only mental fatigue decreased the performance in the simple manual task (−30% [−43, −16] across all thermal conditions; P = 0.002). Cold stress-induced impairments in complex manipulation increase with mental fatigue; yet combined stressors’ effects are no greater than those of mental fatigue alone, which also impairs simple manipulation. Mental fatigue poses a greater challenge to manual dexterity than thermal stress.


2017 ◽  
Vol 62 (3) ◽  
pp. 1000-1013 ◽  
Author(s):  
Lucile Courtial ◽  
Stéphane Roberty ◽  
J.Malcolm Shick ◽  
Fanny Houlbrèque ◽  
Christine Ferrier-Pagès

2018 ◽  
Vol 15 (149) ◽  
pp. 20180448 ◽  
Author(s):  
Jonathan B. Stocking ◽  
Christian Laforsch ◽  
Robert Sigl ◽  
Matthew A. Reidenbach

Corals require efficient heat and mass transfer with the overlying water column to support key biological processes, such as nutrient uptake and mitigation of thermal stress. Transfer rates are primarily determined by flow conditions, coral morphology and the physics of the resulting fluid–structure interaction, yet the relationship among these parameters is poorly understood especially for wave-dominated coral habitats. To investigate the interactive effects of these factors on fluxes of heat and mass, we measure hydrodynamic characteristics in situ over three distinct surface morphologies of massive stony corals in a Panamanian reef. Additionally, we implement a numerical model of flow and thermal transport for both current and wave conditions past a natural coral surface, as well as past three simplified coral morphologies with varying ratios of surface roughness spacing-to-height. We find oscillatory flow enhances rates of heat and mass transfer by 1.2–2.0× compared with unidirectional flow. Additionally, increases in Reynolds number and in surface roughness ratio produce up to a 3.3× and a 2.0× enhancement, respectively. However, as waves begin to dominate the flow regime relative to unidirectional currents, the underlying physical mechanisms mediating transfer rates shift from predominantly turbulence-driven to greater control by inertial accelerations, resulting in larger heat and mass transfer for small surface roughness ratios. We show that for rough corals in wave-dominated flows, novel trade-off dynamics for heat and mass transfer exist between broadly spaced roughness that enhances turbulence production versus narrowly spaced roughness that produces greater surface area. These findings have important implications for differential survivorship during heat-induced coral bleaching, particularly as thermal stress events become increasingly common with global climate change.


2014 ◽  
Vol 13 ◽  
pp. 27-36 ◽  
Author(s):  
Alexander Jueterbock ◽  
Spyros Kollias ◽  
Irina Smolina ◽  
Jorge M.O. Fernandes ◽  
James A. Coyer ◽  
...  

2013 ◽  
Vol 27 (3) ◽  
pp. 142-148 ◽  
Author(s):  
Konstantinos Trochidis ◽  
Emmanuel Bigand

The combined interactions of mode and tempo on emotional responses to music were investigated using both self-reports and electroencephalogram (EEG) activity. A musical excerpt was performed in three different modes and tempi. Participants rated the emotional content of the resulting nine stimuli and their EEG activity was recorded. Musical modes influence the valence of emotion with major mode being evaluated happier and more serene, than minor and locrian modes. In EEG frontal activity, major mode was associated with an increased alpha activation in the left hemisphere compared to minor and locrian modes, which, in turn, induced increased activation in the right hemisphere. The tempo modulates the arousal value of emotion with faster tempi associated with stronger feeling of happiness and anger and this effect is associated in EEG with an increase of frontal activation in the left hemisphere. By contrast, slow tempo induced decreased frontal activation in the left hemisphere. Some interactive effects were found between mode and tempo: An increase of tempo modulated the emotion differently depending on the mode of the piece.


Crisis ◽  
2019 ◽  
Vol 40 (6) ◽  
pp. 413-421 ◽  
Author(s):  
Megan L. Rogers ◽  
Thomas E. Joiner

Abstract. Background: Acute suicidal affective disturbance (ASAD) has been proposed as a suicide-specific entity that confers risk for imminent suicidal behavior. Preliminary evidence suggests that ASAD is associated with suicidal behavior beyond a number of factors; however, no study to date has examined potential moderating variables.  Aims: The present study tested the hypotheses that physical pain persistence would moderate the relationship between ASAD and (1) lifetime suicide attempts and (2) attempt lethality. Method: Students ( N = 167) with a history of suicidality completed self-report measures assessing the lifetime worst-point ASAD episode and the presence of a lifetime suicide attempt, a clinical interview about attempt lethality, and a physical pain tolerance task. Results: Physical pain persistence was a significant moderator of the association between ASAD and lifetime suicide attempts ( B = 0.00001, SE = 0.000004, p = .032), such that the relationship between ASAD and suicide attempts strengthened at increasing levels of pain persistence. The interaction between ASAD and pain persistence in relation to attempt lethality was nonsignificant ( B = 0.000004, SE = 0.00001, p = .765). Limitations: This study included a cross-sectional/retrospective analysis of worst-point ASAD symptoms, current physical pain perception, and lifetime suicide attempts. Conclusion: ASAD may confer risk for suicidal behavior most strongly at higher levels of pain persistence, whereas ASAD and pain perception do not influence attempt lethality.


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