Not Just About Faces in Context: Face-Context Relation Moderates the Impact of Contextual Threat on Facial Trustworthiness.

Recent work showed that the attribution of facial trustworthiness can be influenced by the surrounding context in which a face is embedded: contexts that convey threat make faces less trustworthy. In four studies (N = 388, three preregistered) we tested whether face-context integration is influenced by how faces and contexts are encoded relationally. In Experiments 1a to 1c, face-context integration was stronger when threatening stimuli were attributable to the human action. Faces were judged less trustworthy when shown in threatening contexts that were ascribable (vs. non-ascribable) to the human action. In Experiment 2, we manipulated face-context relations using instructions. When instructions presented facial stimuli as belonging to the "perpetrators" of the threatening contexts, no difference with the control (no-instructions) condition was found in face-context integration. Instead, the effect was reduced when faces were presented as "victims." We discussed the importance of considering relational reasoning when studying face-context integration.

The effect of negative emotion processing on spatial navigation: an experimental study using virtual reality.

Finding one's way in unfamiliar environments is an essential ability. When navigating, people are overwhelmed with an enormous amount of information. However, some information might be more relevant than others. Despite the mounting knowledge about the mechanisms underlying orientational skills, and the notable effects of facial emotions on human behavior, little is known about emotions' effects on spatial navigation. Hereby, this study aimed to explore how exposure to others' negative emotional facial expressions affects wayfinding performances. Moreover, gender differences that characterize both processes were considered. Fifty-five participants (31 females) entered twice in three realistic virtual reality environments: the first time, to encode a route to find an object and then to recall the learned path to reach the same object again. In between the two explorations of the virtual environment, participants were asked to undergo a gender categorization task during which they were exposed to sixty faces showing either neutral, fearful, or angry expressions. Results showed a significant interaction between emotions, time, and gender. In particular, the exposition to fearful faces, but not angry and neutral ones, decreased males' wayfinding performances (i.e., travel times and distance travelled), while females' performances were unaffected. Possible explanations for such gender and emotional dissimilarities are discussed.

Untrusted under threat: on the superior bond between trustworthiness and threat in face-context integration.

The face is a powerful source to make inferences about one's trustworthiness. Recent studies demonstrated that facial trustworthiness is influenced by the level of threat conveyed by the visual scene in which faces are embedded: untrustworthy-looking faces are more likely judged as untrustworthy when shown in threatening scenes. Here, we explore whether this face-context congruency effect is specific to the negative pole of the threat-trust domain. Experiment 1 (N = 89) focused on the differential impact of positive vs. negative face-context congruency within the domains of threat and trust. Negative congruency (i.e. untrustworthy-looking faces in threatening contexts) led to more extreme attributions as opposed to positive congruency (i.e. trustworthy-looking faces in reassuring contexts). Experiment 2 (N = 120) replicated these findings by further showing their domain-specificity. The negativity bias was found in the threat-trust domain, but not when extroverted- vs. introverted-looking faces appeared in happy vs. sad context scenes. Experiment 3 (N = 154, pre-registered) replicated the pattern observed in Experiment 1 while controlling for the extent to which both threatening and reassuring context stimuli were related to the human action. We discussed the theoretical implications of these results for understanding how contextual information is integrated into the evaluation of facial trustworthiness.

Modelling botanical biofiltration of indoor air streams contaminated by volatile organic compounds.

Botanical filtration is a biological-based treatment method suitable for removing hazardous volatile organic compounds (VOCs) from air streams, based on forcing an air flow through a porous substrate and foliage of a living botanical compartment. The pathways and removal mechanisms during VOC bioremediation have been largely investigated; however, their mathematical representation is well established only for the non-botanical components of the system. In this study, we evaluated the applicability of such a modelling scheme to systems which include a botanical compartment. We implemented a one-dimensional numerical model and performed a global sensitivity analysis to measure the input parameters influence on the transient and steady biofilter responses. We found that the most sensitive parameters on the transient-state behaviour were the mass transfer coefficient between gas and solid surfaces, and the fraction of solid surfaces covered by the biofilm; the steady-state response was primarily influenced by the biofilm specific surface area and the fraction of surfaces covered by the biofilm. We calibrated the identified set of parameters and successfully validated the model against data from a pilot-scale installation. The results showed that the application of the model to systems with a botanical compartment is feasible, although under a strict set of assumptions.

Cross-modal impression updating: Dynamic impression updating from face to voice and the other way around.

Research has shown that faces and voices shape impression formation. Most studies have examined either the impact of faces and voices in isolation or the relative contribution of each source when presented simultaneously. However, only a few studies have questioned whether and how impressions formed via one source can be updated due to incremental information gathered from the alternative source. Yet, cross-modal impression updating is key to shed light on person perception. Thus, we tested whether positive and negative face- and voice-based impressions could be updated by inconsistent cross-modal information. In Experiment 1 (N = 130), we tested whether face-based impressions could be updated by (in)consistent voices. In Experiment 2 (N = 262), we compared face-to-voice and voice-to-face impression updating. In Experiment 3 (N = 242), we favoured a more direct comparison of the two types of stimuli (i.e., the co-occurrence of both cue types when the new information is revealed). Results showed that voices have the greatest updating impact and that the updating effect of faces was halved when voices co-occurred for a second time. We discussed these results as evidence of the dynamical evolution of cross-modal impressions.

Modeling of electrokinetic remediation combining local chemical equilibrium and chemical reaction kinetics.

A mathematical model for reactive-transport processes in porous media is presented. The modeled system includes diffusion, electromigration and electroosmosis as the most relevant transport mechanisms and water electrolysis at the electrodes, aqueous species complexation, precipitation and dissolution as the chemical reactions taken place during the treatment time. The model is based on the local chemical equilibrium for most of the reversible chemical reactions occurring in the process. As a novel enhancement of previous models, the local chemical equilibrium reactive-transport model is combined with the solution of the transient equations for the kinetics of those chemical reactions that have representative rates in the same order than the transport mechanisms. The model is validated by comparison of simulation and experimental results for an acid-enhanced electrokinetic treatment of a real Pb-contaminated calcareous soil. The kinetics of the main pH buffering process, the calcite dissolution, was defined by a simplified empirical kinetic law. Results show that the evaluation of kinetic rate entails a significant improvement of the model prediction capability.

Multispecies reactive transport modelling of electrokinetic remediation of harbour sediments.

We implemented a numerical model to simulate transport of multiple species and geochemical reactions occurring during electrokinetic remediation of metal-contaminated porous media. The main phenomena described by the model were: (1) species transport by diffusion, electromigration and electroosmosis, (2) pH-dependent buffering of H+, (3) adsorption of metals onto particle surfaces, (4) aqueous speciation, (5) formation and dissolution of solid precipitates. The model was applied to simulate the electrokinetic extraction of heavy metals (Pb, Zn and Ni) from marine harbour sediments, characterized by a heterogeneous solid matrix, high buffering capacity and aged pollution. A good agreement was found between simulations of pH, electroosmotic flow and experimental results. The predicted residual metal concentrations in the sediment were also close to experimental profiles for all of the investigated metals. Some removal overestimation was observed in the regions close to the anode, possibly due to the significant metal content bound to residual fraction.

Ligand-enhanced electrokinetic remediation of metal-contaminated marine sediments with high acid buffering capacity.

The suitability of electrokinetic remediation for removing heavy metals from dredged marine sediments with high acid buffering capacity was investigated. Laboratory-scale electrokinetic remediation experiments were carried out by applying two different voltage gradients to the sediment (0.5 and 0.8 V/cm) while circulating water or two different chelating agents at the electrode compartments. Tap water, 0.1 M citric acid and 0.1 M ethylenediaminetetraacetic acid (EDTA) solutions were used respectively. The investigated metals were Zn, Pb, V, Ni and Cu. In the unenhanced experiment, the acid front could not propagate due to the high acid buffering capacity of the sediments; the production of OH(-) ions at the cathode resulted in a high-pH environment causing the precipitation of CaCO3 and metal hydroxides. The use of citric acid prevented the formation of precipitates, but solubilisation and mobilisation of metal species were not sufficiently achieved. Metal removal was relevant when EDTA was used as the conditioning agent, and the electric potential was raised up to 0.8 V/cm. EDTA led to the formation of negatively charged complexes with metals which migrated towards the anode compartment by electromigration. This result shows that metal removal from sediments with high acid buffering capacity may be achieved by enhancing the electrokinetic process by EDTA addition when the acidification of the medium is not economically and/or environmentally sustainable.