Behavioural inhibition and valuation of gain/loss are neurally distinct from approach/withdrawal

Gain or omission/termination of loss produces approach; while loss or omission/termination of gain produces withdrawal. Control of approach/withdrawal motivation is distinct from valuation of gain/loss and does not entail learning – making “reward” and “punishment” ambiguous. Approach-withdrawal goal conflict engages a neurally distinct Behavioural Inhibition System, which controls “anxiety” (conflict/passive avoidance) but not “fear” (withdrawal/active avoidance)

Survival circuits and risk assessment

Risk assessment (RA) behaviour is unusual in the context of survival circuits. An external object elicits eating, mating or fleeing; but conflict between internal approach and withdrawal tendencies elicits RA-specific behaviour that scans the environment for new information to bring closure. Recently rodent and human threat responses have been compared using ‘predators’ that can be real (e.g. a tarantula), robot, virtual, or symbolic (with the last three rendered predatory by the use of shock). ‘Quick and dirty’ survival circuits in the periaqueductal grey, hypothalamus, and amygdala control external RA behaviour. These subcortical circuits activate, and are partially inhibited by, higher-order internal RA processes (anxiety, memory scanning, evaluation and sometimes — maladaptive rumination) in the ventral hippocampus and medial prefrontal cortex

Coronavirus (COVID-19) in the United Kingdom: A personality-based perspective on concerns and intention to self-isolate

Objectives Public behaviour change is necessary to contain the spread of coronavirus (COVID‐19). Based on the reinforcement sensitivity theory (RST) framework, this study presents an examination of individual differences in some relevant psychological factors. Design Cross‐sectional psychometric. Methods UK respondents (N = 202) completed a personality questionnaire (RST‐PQ), measures of illness attitudes, concerns about the impact of coronavirus on health services and socio‐economic infrastructures, personal safety, and likelihood of voluntary self‐isolation. Results Respondents most concerned were older, had negative illness attitudes, and scored higher on reward reactivity (RR), indicating the motivation to take positive approach action despite prevailing worry/anxiety. Personal safety concerns were highest in those with negative illness attitudes and higher fight–flight–freeze system (FFFS, reflecting fear/avoidance) scores. Results suggest people are experiencing psychological conflict: between the urge to stay safe (FFFF‐related) and the desire to maintain a normal, pleasurable (RR‐related) life. Ways of ameliorating conflict may include maladaptive behaviours (panic buying), reflecting reward‐related displacement activity. Intended self‐isolation related to FFFS, but also low behavioural inhibition system (related to anxiety) scores. Older people reported themselves less likely to self‐isolate. Conclusions Interventions need to consider individual differences in psychological factors in behaviour change, and we discuss relevant literature to inform policy makers and communicators

Double layer formation in the expanding region of an inductively coupled electronegative plasma

Double-layers (DLs) were observed in the expanding region of an inductively coupled plasma with $\text{Ar}/\text{SF}\_6$ gas mixtures. No DL was observed in pure argon or $\text{SF}\_6$ fractions below few percent. They exist over a wide range of power and pressure although they are only stable for a small window of electronegativity (typically between 8\% and 13\% of $\text{SF}\_6$ at 1mTorr), becoming unstable at higher electronegativity. They seem to be formed at the boundary between the source tube and the diffusion chamber and act as an internal boundary (the amplitude being roughly 1.5$\frac{kT\_e}{e}$)between a high electron density, high electron temperature, low electronegativity plasma upstream (in the source), and a low electron density, low electron temperature, high electronegativity plasma downstream

Experimental investigation of double layers in expanding plasmas

Double layers (DLs) have been observed in a plasma reactor composed of a source chamber attached to a larger expanding chamber. Positive ion beams generated across the DL were characterized in the low plasma potential region using retarding field energy analyzers. In electropositive gases, DLs were formed at very low pressures between 0.1 and 1 mTorr with the plasma expansion forced by a strongly diverging magnetic field. The DL remains static, robust to changes in boundary conditions, and its position is related to the magnetic field lines. The voltage drop across the DL increases with decreasing pressure, i.e., with increasing electron temperature around 20 V at 0.17 mTorr. DLs were also observed in electronegative gases without a magnetic field over a greater range of pressure 0.5 to 10 mTorr. The actual profile of the electronegative DL is very sensitive to external parameters and intrusive elements, and they propagate at high negative ion fraction. Electrostatic probes measurements and laser-induced photodetachment show discontinuities in all plasma parameters electron density, electron temperature, negative ion fraction at the DL position. The voltage drop across the electronegative DL is about 8 V, is independent of the gas pressure and therefore of the electron temperature