Do emotional faces capture attention, and does this depend on awareness? Evidence from the visual probe paradigm

The visual probe (VP) paradigm provides evidence that emotional stimuli attract attention. Such effects have been reported even when stimuli are presented outside of awareness. These findings have shaped the idea that humans possess a processing pathway that detects evolutionarily significant signals independently of awareness. Here, we addressed 2 unresolved questions: First, if emotional stimuli attract attention, is this driven by their affective content, or by low-level image properties (e.g., luminance contrast)? Second, does attentional capture occur under conditions of genuine unawareness? We found that observers preferentially allocated attention to emotional faces under aware viewing conditions. However, this effect was best explained by low-level stimulus properties, rather than emotional content. When stimuli were presented outside of awareness (via continuous flash suppression or masking), we found no evidence that attention was directed toward emotional face stimuli. Finally, observer's awareness of the stimuli (assessed by d') predicted attentional cuing. Our data challenge existing literature: First, we cast doubt on the notion of preferential attention to emotional stimuli in the absence of awareness. Second, we question whether effects revealed by the VP paradigm genuinely reflect emotion-sensitive processes, instead suggesting they can be more parsimoniously explained by low-level variability between stimuli. (PsycINFO Database Record (c) 2019 APA, all rights reserved)

Are visual threats prioritized without awareness? A critical review and meta analysis involving 3 behavioral paradigms and 2696 observers

Given capacity limits, only a subset of stimuli 1 give rise to a conscious percept. Neurocognitive models suggest that humans have evolved mechanisms that operate without awareness and prioritize threatening stimuli over neutral stimuli in subsequent perception. In this meta analysis, we review evidence for this ‘standard hypothesis’ emanating from three widely used, but rather different experimental paradigms that have been used to manipulate awareness. We found a small pooled threat-bias effect in the masked visual probe paradigm, a medium effect in the binocular rivalry paradigm and highly inconsistent effects in the breaking continuous flash suppression paradigm. Substantial heterogeneity was explained by the stimulus type: the only threat stimuli that were robustly prioritized across all three paradigms were fearful faces. Meta regression revealed that anxiety may modulate threat biases, but only under specific presentation conditions. We also found that insufficiently rigorous awareness measures, inadequate control of response biases and low level confounds may undermine claims of genuine unconscious threat processing. Considering the data together, we suggest that uncritical acceptance of the standard hypothesis is premature: current behavioral evidence for threat-sensitive visual processing that operates without awareness is weak

A novel chlorhexidine-hexametaphosphate coating for titanium with antibiofilm efficacy and stem cell cytocompatibility

Abstract Dental implants are an increasingly popular way to replace missing teeth. Whilst implant survival rates are high, a small number fail soon after placement, with various factors, including bacterial contamination, capable of disrupting osseointegration. This work describes the development of chlorhexidine-hexametaphosphate coatings for titanium that hydrolyse to release the antiseptic agent chlorhexidine. The aim was to develop a coating for titanium that released sufficient chlorhexidine to prevent biofilm formation, whilst simultaneously maintaining cytocompatibility with cells involved in osseointegration. The coatings were characterised with respect to physical properties, after which antibiofilm efficacy was investigated using a multispecies biofilm model, and cytocompatibility determined using human mesenchymal stem cells. The coatings exhibited similar physicochemical properties to some implant surfaces in clinical use, and significantly reduced formation of multispecies biofilm biomass up to 72 h. One coating had superior cytocompatibility, with mesenchymal stem cells able to perform normal functions and commence osteoblastic differentiation, although at a slower rate than those grown on uncoated titanium. With further refinement, these coatings may have application in the prevention of bacterial contamination of dental implants at the time of surgery. This could aid a reduction in rates of early implant failure

Progress Toward National Estimates of Police Use of Force

This research builds on three decades of effort to produce national estimates of the amount and rate of force used by law enforcement officers in the United States. Prior efforts to produce national estimates have suffered from poor and inconsistent measurements of force, small and unrepresentative samples, low survey and/or item response rates, and disparate reporting of rates of force. The present study employs data from a nationally representative survey of state and local law enforcement agencies that has a high survey response rate as well as a relatively high rate of reporting uses of force. Using data on arrests for violent offenses and the number of sworn officers to impute missing data on uses of force, we estimate a total of 337,590 use of physical force incidents among State and local law enforcement agencies during 2012 with a 95 percent confidence interval of +/- 10,470 incidents or +/- 3.1 percent. This article reports the extent to which the number and rate of force incidents vary by the type and size of law enforcement agencies. Our findings demonstrate the willingness of a large proportion of law enforcement agencies to voluntarily report the amount of force used by their officers and the relative strengths and weaknesses of the Law Enforcement Management and Administrative Statistics (LEMAS) program to produce nationally representative information about police behavior

Individual differences in search and monitoring for color targets in dynamic visual displays

Many jobs now involve the monitoring visual representations of data that change over time. Monitoring dynamically changing displays for the onset of targets can be done in two ways: detecting targets directly post their onset or predicting their onset from the prior state of distractors. In the present study, participants? eye movements were measured as they monitored arrays of 108 colored squares whose colors changed systematically over time. Across three experiments, the data show that participants detected the onset of targets both directly and predictively. Experiments 1 and 2 showed that predictive detection was only possible when supported by sequential color changes that followed a scale ordered in color space. Experiment 3 included measures of individual differences in working memory capacity (WMC) and anxious affect and a manipulation of target prevalence in the search task. It found that predictive monitoring for targets, and decisions about target onsets, were influenced by interactions between individual differences in verbal and spatial WMC and intolerance of uncertainty, a characteristic that reflects worry about uncertain future events. The results have implications for the selection of individuals tasked with monitoring dynamic visual displays for target onsets

Chromosomal copy number variation, selection and uneven rates of recombination reveal cryptic genome diversity linked to pathogenicity

This project was funded by the UK Natural Environmental Research Council (NERC) grant NE/E006701/1, the European Research Council (ERC) grant 260801-BIG_IDEA, the Swiss National Science Foundation grant 31-125099 and the Biodiversa project RACE: Risk Assessment of Chytridiomycosis to European Amphibian Biodiversity (http://www.bd-maps.eu). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Droplet size development in a DISI injector fuel spray

In this work, Phase Doppler Anemometry (PDA) measurements are used to test the hypothesis that the mean droplet size in Direct Injection Spark Ignition (DISI) engine fuel spray increases with distance from the injector due to the evaporation of the smaller droplets. In order to understand the role of evaporation, two velocity components and drop size PDA measurements were performed for one plume of a DISI injector using two fuels with widely differing vapour pressures. The measurements were taken along the plume centreline at four different vertical distances from the injector tip between 20 to 50 mm. on the plume centreline to evaluate the development of droplet size distributions along the plume. Measurements are also made across the plume (perpendicular to the plume centreline) at the 30 and 50 mm locations. Measurements using PDA closer to the injector are more difficult due to the high spray density (particularly apparent at 20mm or closer to the injector). A data fitting process is suggested using joint probability distribution functions (JPDFs) to reduce the effect of statistical significance where data rates are low. This improves the description of the PDA derived drop size distribution in regions where the data validation rate is poor. It is found that the evaporation is not the main cause for droplet size increase along the plume. The most likely reason for the increase of the Sauter Mean Diameter (SMD) with distance from the injector is that the smaller droplets move away from the plume centreline through turbulent diffusion at a higher rate compared to larger droplets. Higher axial momentum of the larger droplets reduces their response to turbulent velocity fluctuations and hence their path-lines are less prone to stray from their initial trajectory

Impact of gasoline direct injection fuel injector hole geometry on spray characteristics under flash boiling and ambient conditions

The effect of injector nozzle design on the Gasoline Direct Injection (GDI) fuel spray characteristics under atmospheric and flash boiling conditions was investigated using Phase Doppler Anemometry (PDA) measurements. To understand the impact of hole diameter and conicity, experiments were conducted on two bespoke 3-hole injectors in a pressure and temperature controlled constant volume chamber and in the open air. The measurements were taken radially outward from the injector axis to the outer extent of the plume at distances of 15 mm, 25 mm and 40 mm from the injector tip. Observations of the influence of surrounding gas and temperature conditions and hole design on the injector spray performance were made. Under non-flash boiling conditions, it was found that the injection pressure dictates the length of the spray penetration before collapse occurs, with an increase in pressure resulting in an increase in this length. Comparison of mean velocity and droplet diameter data are also made to understand the performance under flash boiling conditions. Results show that, under flash boiling conditions, the droplet velocity significantly increases while the droplet size reduces. More importantly, it is found that the impact of the flash boiling environment on sprays of different hole geometries is different. Some hole designs offer more resistance against spray collapse. It was found that the mid-sized of the three hole diameters tested here was found to produce a spray that more readily collapsed than that of the smaller or larger hole diameters. In addition, it was found that under flash boiling conditions, the convergent hole had a greater propensity to exhibit spray collapse

Experimental investigation of the effect of high pressure nozzle geometry on spray characteristics

Phase Doppler Anemometry (PDA) measurements [1] are applied to low length to diameter ratio (L/D) multi-hole nozzles operating with at high fuel pressure (20 MPa) that are implemented in the new Euro6 generation of Gasoline Direct Injection engines. For these multi-jets spray, the authors intend to demonstrate; the importance of the spray shape, the effect of hole design and the reorganisation dynamic of the drop size distribution by turbulent mixing. To do so, we report significant experimental effort along with careful data reduction, exercised to understand the spray behaviour, in particular separating the sources of experimental uncertainty from the flow physics. A practical methodology is adopted as a compromise between measurement effort, error removal, and the need to understand underlying physical processes within the spray plume. The present work focuses mostly on the drop size and velocity profiles (two-component) perpendicular to the plume direction