Frédéric Dehais
email: frederic.dehais@isae.fr

Julia Behrend

Vsevolod Peysakhovich

Mickaël Causse

Christopher D Wickens

Pilot Flying and Pilot Monitoring's Aircraft State Awareness During Go-Around Execution in Aviation: A Behavioral and Eye Tracking Study

Objective: Examination of the performance and visual scanning of aircrews during final approach and an unexpected go-around maneuver.

Background: Accident and incident analyses have revealed that goaround procedures are often imperfectly performed because of their complexity, their high time stress, and their rarity of occurrence that avails little time for practice. We wished to examine this experimentally and establish the frequency and nature of errors in both flight-performance and visual scanning.

Method: We collected flight-performance (e.g., errors in procedures, excessive flight deviations) and eye-tracking data of 12 flight crews who performed final approach and go-around flight phases in realistic full-flight transport-category simulators.

Results: The pilot performance results showed that two thirds of the crews committed errors including critical trajectory deviations during go-arounds, a precursor of accidents. Eye-tracking analyses revealed that the cross-checking process was not always efficient in detecting flight-path deviations when they occurred. Ocular data also highlighted different visual strategies between the 2 crew members during the 2 flight phases.

Conclusion: This study reveals that the go-around is a challenging maneuver. It demonstrates the advantages of eye tracking and suggests that it is a valuable tool for the explicit training of attention allocation during go-arounds to enhance flight safety.

In commercial aviation, the final-approach phase is one of the most dynamic flight segments, for which safety margins are minimum and time pressure is maximum. Numerous undesired external events or crew failure to stabilize the flight path or to configure the aircraft for landing could lead to the execution of a go-around. Flight crews, composed of a pilot flying (PF) and a pilot monitoring (PM), are trained to land the aircraft or to perform a go-around according to standard operating procedures (U.S. Department of Transportation, 2015). During go-around, the PF's task is to manage the missed-approach flight path while giving instructions to the PM (e.g., retracting the flaps and the landing gear). The PM carefully monitors the flight path and the status of the aircraft and executes the PF's instructions.

Despite this defined task distribution, more than 25 critical events occurred during go-around execution between 1985 and 2010. Their consequences were serious in terms of fatalities (954;[START_REF]Study of aeroplane state awareness during go-around[END_REF]. The Bahrain accident in 2006 [START_REF]Study of aeroplane state awareness during go-around[END_REF] is an example when the captain applied incorrect pitch control during go-around, was distracted by an auditory warning, and continued until the aircraft impacted the sea. The investigation commission highlighted that the copilot (PM) did not perform his monitoring duties correctly [START_REF] Bea | Accident 23 August 2000 on approach to Bahrain A320 (BEA a40-ek000823[END_REF]. As emphasized by the National Transportation Safety Board (NTSB) and the International Civil Aviation Organization (ICAO), pilots' poor flight-path monitoring was a contributive factor in most of major civilian accidents (NTSB, 2013), such as Colgan Air Flight 3407 [START_REF] Spangler | Loss of control on Approach Colgan Air, Inc., operating as Continental Connection Flight 3407[END_REF], Asiana Air Flight 214 (NTSB, 2015), Turkish Airlines Flight 1951[START_REF] Safety | Crashed during approach, Boeing 737-800[END_REF], or more recently UPS Airlines Flight 1354 (NTSB, 2013) to name a few (UK Civilian Aviation Authority, 2013). Consistently, the Active Pilot Monitoring Group identified several contributing factors to these events, among which was a "corporate climate that does not emphasize on monitoring" (FSF, 2014).

To determine the nature and the frequency of errors and the pilots' related visual scanning during go-around, the BEA (the French Accident Investigation Bureau) initiated the Aeroplane State Awareness during Go-Around (ASAGA) study [START_REF]Study of aeroplane state awareness during go-around[END_REF]. This study consisted of two main components: a survey and an observational eye-tracking study in full-flight simulators, the core of this article.

The results of the first component, the survey, reported that a go-around was a rather infrequent event, although it is considered as a standard maneuver regularly practiced in airlines' flight simulators. Indeed, the survey showed that a medium-haul flight crew performed on average one go-around per year during commercial flight, whereas a long-haul flight crew experienced one goaround every 5 to 10 years [START_REF]Study of aeroplane state awareness during go-around[END_REF]. This rather low-frequency experience in realistic settings may leave the pilots ill-equipped to switch from an expected goal (landing) to a highly-dynamic procedure that may challenge humans' mental capacities. Pilots' response to low-probability events represents a critical component for aviation safety [START_REF] Pinet | Book review: Facing the unexpected in flight[END_REF][START_REF] Wickens | Identifying black swans in NextGen: Predicting human performance in off-nominal conditions[END_REF]. The results of the survey (BEA, 2013) also stressed that pilots identified three critical elements that made the execution of the go-around complex. First, a dense communication with air traffic control (ATC) was cited as a possible overloading factor that disturbed the pilots' conscious plan of actions, particularly when clearance differed from the expected procedurespecified go-around trajectory. Second, complex automation management, excessive thrust power, and rapid, precise actions were considered factors that induced time pressure. Third, pilots were unanimous in reporting confusion, attentional impairment, and poor crew-resource management leading to poor task sharing during the go-around maneuver. This situation can reduce flying performance, as previous research has shown the influence of stress on cognitive performance in aviation [START_REF] Dehais | The perseveration syndrome in the pilot's activity: Guidelines and cognitive countermeasures[END_REF][START_REF] Pizziol | Petri net-based modelling of human-automation conflicts in aviation[END_REF][START_REF] Starcke | Decision making under stress: A selective review[END_REF][START_REF] Stokes | Flight stress: Stress, fatigue, and performance in aviation[END_REF]. In particular, time pressure might direct the flight crew to use fewer channels of information [START_REF] Stokes | Time-stressed decision-making: A study of expert and novice aviators[END_REF]Tessier & Dehais, 2012).

The objective of the second component of the ASAGA study, namely the observational simulator study, was to assess pilots' monitoring abilities during final approach and go-around. An interesting prospect to understand a pilot's visual scan is to consider eye tracking. Several studies confirmed that measuring dwell times in the cockpit offered an insight into pilots' visual behavior [START_REF] Dehais | Embedded eye tracker in a real aircraft: New perspectives on pilot/ aircraft interaction monitoring[END_REF][START_REF] Kasarskis | Comparison of expert and novice scan behaviors during VFR flight[END_REF][START_REF] Mumaw | Analysis of pilots' monitoring and performance on an automated flight deck[END_REF][START_REF] Reynal | Investigating pilot's decision making when facing an unstabilized approach: An eye tracking study[END_REF][START_REF] Sarter | Pilots' monitoring strategies and performance on automated flight decks: An empirical study combining behavioral and eye-tracking data[END_REF][START_REF] Wickens | Attentionsituation awareness (A-SA) model of pilot error[END_REF]. Additionally, the computation of the number of fixations and saccades can reveal basic visual strategies, and it can be an indicator of information processing [START_REF] Dehais | Automation surprise in aviation: Real-time solutions[END_REF][START_REF] Regis | Ocular metrics for detecting attentional tunnelling[END_REF].

To link flight performance and eye movements, we designed a scenario in which crews performed a final approach and a go-around procedure in realistic full-flight (per the National Aviation Authority [NAA] definition; meaning a high technical level of flight simulation) transport-category aircraft simulators. One novelty of this study was to collect both the PF's and PM's eye movements, a goal that has rarely been achieved before [START_REF] Reynal | Pilot flying vs. Pilot monitoring during the approach phase: An eye-tracking study[END_REF]. The scenario included the main critical features identified during the survey: a nonanticipated go-around (i.e., ATC requested the go-around at the last moment) and a nonstandard go-around trajectory. Our goal was to determine the percentage of pilots who would make errors in attempting the go-around and the nature and frequency of these errors. We collected eye-tracking data to assess the effect of the go-around maneuver on the PF's and PM's dwell time. Additionally, our objective was to relate visual behavior to the errors of commission and omission in the go-around and to determine how visual behavior affected performance and determine how instrument-scanning behavior differed from expectations regarding the pilot role (PF vs. PM).

Material and Method

Participants

Twenty-four French professional airline pilots (PFs M age = 49.8 years, SD = 4.9, mean flight experience = 14,540 hr, SD = 2573.51; PM's M age = 41 years, SD = 4.7, mean flight experience = 8743.5 hr, SD = 2733.3; 2 females: 1 PF and 1 PM) voluntarily participated in this observational study. Each of the 12 flight crews was composed of a captain (PF) and a first officer (PM). As in real airline situations, crews were not necessarily familiar with each other and were randomly paired. All participants were informed about the study and gave written consent before participating.

Protocol

Two different twin-engine simulators were used for the experiment: seven crews flew on a Boeing 777 fullflight simulator and five crews flew on an Airbus 330 full-flight simulator. Aircraft type was not of fundamental interest in the study. The crews were instructed that the simulator sessions aimed to study the human visual system during a standard flight. Importantly, we did not inform the pilots about a forthcoming go-around. However, pilots knew the published go-around procedure for a selected runway. This is a specific element of the approach briefing. To increase pilots' workloads, (a) the flight was conducted during the night, (b) ATC requested the go-around at the last moment, and (c) ATC's instructions differed from the published missed approach procedure, as sometimes happens during go-arounds.

The general scenario was as follows: a night flight lasting about 40 min, taking off from Bordeaux and heading to Lyon. During descent, ATC asked the pilots to perform a manual Instrument Landing System (ILS) approach to Runway 35L. The runway became perfectly visible when the aircraft descended below a height of 1,000 ft. Without advance notice, at a height below 200 ft, ATC contacted the crew to indicate the presence of traffic on the runway and asked for an immediate go-around. Unlike the published go-around, which requires the crew to climb in the runway's axis on a magnetic heading of 354 to an altitude of 5,000 ft, ATC instructed the crew to turn left on a heading of 340°and to climb and level off at an altitude of 2,500 ft. This ATC request induced a go-around at low altitude with a disruption caused by the new trajectory. We expected that this maneuver combining a turn and a simultaneous climb with an altitude limitation would surprise the crew and increase time pressure, making flight-path and energy management more difficult.

Measurements

Our analysis first focused on the crews' performance, such as response time and errors. Second, we performed group analyses on dwell times and basic eye movements to determine how the onset and the management of the go-around affected the PF's and PM's visual attention allocation. Third, we related crews' errors to eye movements through quantitative and qualitative analyses to determine how PF and PM visual scan affected flight performance.

Pilot Flight-Performance Analysis

A high-definition (HD) video camera was set up in the cockpit to allow us to monitor the flight parameters displayed on the flight deck, crews' actions, and their verbal communications. We analyzed crews' compliance with standard operating procedures; that is, pilots' actions and the correct order of these actions during go-around. The go-around is announced by the PF, who applies full power and adopts a positive climb, rotating to the go-around pitch target. The PM retracts the flaps and monitors the vertical-speed indicator. Once the positive climb is confirmed by the PM, the PF orders "gear up," and the action is executed by the PM. During the execution of the maneuver, the crews must carefully monitor the flight path and the speed. In summary, we used the HD camera to analyze the crews' reaction time to execute the maneuver (i.e., from the moment they applied full-throttle to the moment they reached the requested altitude-2,500 ft-with the correct heading, 340°). The crews' ability to perform the expected actions and to read back the clearance instruction was also assessed with the video material. The BEA experts identified flight path deviation from the go-around requested trajectory (340°, 2,500 ft): Any lateral deviations exceeding ±20°and vertical deviations greater than 200 ft were considered flight-path excursions. After the experiment, a debriefing was conducted to collect the PM's and PF's subjective data.

Eye Tracking

The participants' eye movements were recorded using two 50 Hz head-mounted Pertech® eye-trackers. The participants' fixations were mapped on an image of reference, chosen for each participant so that it contained 14 areas of interest (AOIs; see Figure 1). However, to reduce the number of comparisons, the data analysis was focused primarily on the six AOIs that received the majority of visual scans.

For each participant, we analyzed two flight phases: final approach starting from 2,500 ft, and goaround (until the stabilization of the aircraft at 2,500 ft). For the purposes of analysis, the data were categorized by aircraft type (2: Boeing, Airbus), pilot role (2: PF, PM), flight phase (2: final approach, go-around), and the six most viewed AOIs. First, mean dwell time on each of the six AOIs was calculated. Second, to perform complementary basic analyses of eye movements, we determined the occurrence of fixations and saccades through the whole eye-tracking recording. Eye movements under 30°/s and not exceeding 1°in dispersion were considered as fixations (as in [START_REF] Dehais | Automation surprise in aviation: Real-time solutions[END_REF]. The computation of an eye metric based on the fixation and saccade ratio was then used to express the balance between the different visual strategies of explore (visual search) and exploit (i.e., visual processing) [START_REF] Goldberg | Computer interface evaluation using eye movements: Methods and constructs[END_REF]. Similar to [START_REF] Dehais | Automation surprise in aviation: Real-time solutions[END_REF], we first selected eye movements that resulted in a Cohen's d value greater than .8, considered a large effect size [START_REF] Cohen | Statistical power analysis[END_REF]. This led us to identify four categories of eye movements: (a) short fixations of 40 to 80 ms, (b) medium fixations of 180 to 220 ms, (c) long fixations of 340 to 500 ms, and (d) saccades of 140 to 260 ms. We then constructed a modified ratio defined as R = (short fixations + saccades)/(medium fixations + long fixations). High R values indicate explore behavior (visual search) whereas low R values expressed exploit behavior (processing; [START_REF] Dehais | Automation surprise in aviation: Real-time solutions[END_REF][START_REF] Goldberg | Computer interface evaluation using eye movements: Methods and constructs[END_REF].

Results

Pilot Performance During the Execution of the Go-Around

All of the participants correctly initiated the go-around procedure and managed to stabilize the aircraft in accordance with the ATC clearance. The mean response time to complete the go-around maneuver (i.e., heading 340°, altitude 2,500 ft) was 74.7 s (SD = 14.92). Only 3 aircrews (1, 3, 11) out of 12 were able to read back the complete go-around clearance on their initial response (i.e., heading 340, altitude 2,500), and 2 aircrews remembered only one piece of information (2 and 5) and thus had to ask ATC to repeat the missed instructions. The remaining 7 crews had to call back ATC to repeat the complete clearance so as to dial the settings in the flight control unit (FCU). Six crews experienced lateral (2, 8), vertical (7, 9, 10), or both lateral and vertical (11) trajectory deviation, mostly due to poor interaction with the FCU (2,7,9,10,11). Eventually, one PM (1) did not retract the landing gear. Table 1 provides detailed information about each crew's performance. No overt differences in performance (i.e., time to complete the go-around, errors) were observable between the two types of aircraft simulated. Eye Tracking Analyses at the Group Level: Assessing the Impact of the Go-Around on PF's and PM's Visual Attention Distribution Inferential statistical analyses were performed using R with the "Ezanova" package (see https://www.rproject.org/). Repeated-measures analysis of variance (ANOVA) was used to examine main and interaction effects of the AOIs, the pilot role (PF or PM), and the flight phase (final approach and go-around).

AOI Percent Dwell Time

Preliminary analysis of the eye-tracking data revealed that a vast majority (79%) of the fixations were focused on the six most-viewed AOIs (i.e., mean dwell time above 5% in at least one condition). Hence, the subsequent analyses of AOI dwell times were exclusively focused on AOIs defining out-the-window (OTW), Attitude Indicator (AI), airspeed (AS), altimeter (ALT), navigation display (ND), FCU.

An initial 6 × 2 (6 AOIs × 2 types of aircraft) ANOVA showed no main effect of aircraft type, F(5, 50) = 2.92, p > .05, η 2 p = .005; and no Aircraft Type × AOI interaction effect, F(5, 50) = 0.46, p > .05, η 2 p = .04). This result was expected, as the flight decks of these two airplanes are similar. All subsequent analyses were therefore collapsed over airplane type.

To check the consistency of our data, we compared them with those of [START_REF] Sarter | Pilots' monitoring strategies and performance on automated flight decks: An empirical study combining behavioral and eye-tracking data[END_REF]see Steelman, McCarley, & Wickens, 2011) to suggest that there is generally a close correspondence between the PF's scanning behavior recorded here, and the one of the PF in the 747 simulation [START_REF] Sarter | Pilots' monitoring strategies and performance on automated flight decks: An empirical study combining behavioral and eye-tracking data[END_REF] during the approach phase. Across five AOIs in our analyses (FCU data were removed because equivalent data were not available from [START_REF] Sarter | Pilots' monitoring strategies and performance on automated flight decks: An empirical study combining behavioral and eye-tracking data[END_REF], the correlation in mean dwell time between the two studies indicated a good agreement (r = .88, p < .10).

A 6 × 2 × 2 (6 AOIs × 2 pilots × 2 flight phases) ANOVA on these data yielded a significant effect of AOI, F(5, 110) = 60.05, p < .0001, η 2 p = 0.73; and a significant AOI × Pilot interaction, F(5, 110) = 21.21, p < .0001, η 2 p = 0.49.

Our particular interest was in the shift of (a) total visual attention of the crew, and (b) differential monitoring by each crew member, as the aircraft moves from a normal final approach to an offnominal go-around. The data are presented in a different panel for each AOI (see Figure 2). The different changes in scanning behaviors within Figure 2, discussed here, were statistically significant as indicated by the three-way interaction between pilot, flight phase, and AOI, F(5, 110) = 8.391, p < .0001, η 2 p = 0.27. These scanning behaviors within each panel are then analyzed by the 2 × 2 ANOVA on the four data points within each:

• Both pilots neglected the outside world (OTW) scanning (second panel) during the go-around, just as both paid more attention to monitor carefully the airspeed indicator (AS; third panel) so it does not drop below minimum (stall) or exceed maximum (velocity flaps extended limit) values, and the navigation display (ND; fifth panel). These are reflected in the main effect of flight phase within each of these three AOIs: OTW, F(1, 22) = 204, p < .001; AS, F(1, 22) = 32.8, p < .001; ND, F(1, 22) = 10.1, p < .01. • A differential shift is shown on the attitude indicator (AI; first panel), as revealed by a significant Pilot × Phase interaction, F(1, 22) = 13.2, p < .01, which received substantially more attention from the PF (Honest Significant Difference [HSD] < .001) during the go-around. The PF fixated more on the AI than did the PM (p < .001) when performing the go-around to apply the correct reference pitch angle to avoid a stall. Another differential shift, to the FCU, was revealed in the significant Pilot Role × Flight Phase interaction, F(1, 22) = 17.5, p < .001, which also confirmed that the FCU (sixth panel) received much more attention shift from the PM than from the PF (HSD < .01.)

Eye Movements and Explore/Exploit Ratio Following the procedures of [START_REF] Dehais | Automation surprise in aviation: Real-time solutions[END_REF], we measured the explore/exploit ratio. We conducted a 2 (pilot role) × 2 (flight phase) ANOVA to examine the interaction between the pilot role and the flight phase on the ratio. Tukey's HSD test was used for post-hoc comparisons.

The data for the constructed explore/exploit ratio are shown in Figure 3, and the ANOVA revealed the main effect of the pilot role, F(1, 11) = 10.09, p < .01, η2 = 0.48, corresponding to higher explore activity for PM. The interaction between the two factors was significant, F(1, 11) = 18.03, p < .01, η2 = 0.62. As Figure 3 shows, during go-around, but not approach, the PM engaged in much more exploratory behavior than did the pilot. The mean ratio of the PF during the go-around procedure was significantly lower than the ratio for the PM during final approach (HSD < .05) and go-around (HSD < .01) phases. Pilot Performance and Related Eye Tracking Analyses: Assessing the Efficiency of the PF's and the PM's Visual Scan and Cross-Checking

The previous statistical analyses highlighted the finding that both pilots exhibited different ocular behaviors during the go-around. Nevertheless, these analyses at a group level could not distinguish between crews who effectively managed the go-around and crews who did not. For convenience, we labeled them as best performing crews and poorest performing crews, respectively.

To examine what features of scanning might differentiate the two cases, we selected the six best crews, who did not experience any of the BEA-scored flight path deviations (Crews 1,3,4,5,6,12), and the six poorest who did (Crews 2,7,8,9,10,11). We performed a logistic regression with the six main AOIs as predictors and the group performance as binomial outcome (i.e., best vs poorer). This regression yielded only one of the AOIs, airspeed, that distinguished the two skill levels (p = .03). Figure 4 depicts that this effect is particularly important for the PMs. PMs in poorer crew groups paid considerably (40%) less attention to airspeed monitoring than the ones in the best performing crew groups.

To gain a deeper understanding at an individual level, we then conducted qualitative analyses to examine pilots' performance errors (PM errors vs. PF errors) and their ability to "visually" crosscheck critical flight parameters (see Table 1). For instance, we checked to determine if the PFs glanced at the landing-gear indicator right after the PFs' action because one PM forgot to retract it. We also verified if the PFs checked the PMs' settings by glancing at the ND or at the FCU because some PMs did not interact correctly with the autoflight panel.

Figure 5 illustrates poor monitoring skills of one pilot (PM 11; see Table 1). This PM exhibited excessive focus on entering the data into the FCU (2,500 ft, 340°) for 15 s to the detriment of the monitoring of the flight deck. Black dots indicate the current gaze position, time origin being aligned to the initiation of the go-around procedure.

Table 1 gave us some insights into the visual cross-checking behavior of both pilots. To gain a deeper understanding of the crews' overall visual attention on important flight-path parameters during go-around, we examined how much time the crew neglected critical parameters related to the energy and the trajectory of the airplane. Therefore, we measured the maximum lapse of time during which those AOIs were not glanced at by any of the crew members, PM or PF (i.e., the period of neglect or "first passage time;" [START_REF] Moray | Monitoring behavior and supervisory control[END_REF]. Figure 6 represents the crews' median values of the longest period without a fixation on the primary flight parameters: speed, attitude indicator, altitude indicator and ND. Figure 6 shows that primary flight parameters such as the airspeed or altitude were sometimes not monitored by any of the crew members during more than 12 s or 14 s, respectively. However this neglect period did not differ statistically between the two performance groups.

Discussion

In this observational study, 12 crews, equipped with eye trackers, were placed in realistic flight simulators, facing a demanding go-around scenario. Our measurements allowed us to address the following questions. How Did the Crew Manage the Go-Around Execution?

The analysis of pilot performance revealed that all flight crews managed to stabilize the aircraft in accordance with ATC clearances. However, debriefing results indicated that the execution of the maneuver was particularly demanding. During the debriefing session, all PMs-except one-highlighted the complexity of the procedure and reported difficulties. In particular, they felt overwhelmed by the PF's callouts, ATC particular instructions, and the numerous actions to be performed during a short period of time. As stated by one pilot, "The diverse nature of the tasks and the speed at which they must be performed generate stress, notably when the startle effect is also included in the situation. Since stress reduces our ability to cope with complex actions, performance levels drop during go-arounds."

Moreover, only 3 crews out of 12 were able to correctly read back the complete ATC instructions while programming them rapidly in the flight-control panel. Recalling ATC instructions involves working memory abilities [START_REF] Helleberg | Effects of data link modality and display redundancy on pilot performance: An attentional perspective[END_REF][START_REF] Risser | ATC commands executed in speech and text formats: Effects of task interference[END_REF][START_REF] Taylor | Cognitive ability, expertise, and age differences in following air-traffic control instructions[END_REF][START_REF] Taylor | The effects of information load and speech rate on younger and older aircraft pilots' ability to execute simulated air-traffic controller instructions[END_REF] that are known to be negatively affected by pilot workload [START_REF] Durantin | Processing functional near infrared spectroscopy signal with a Kalman filter to assess working memory during simulated flight[END_REF][START_REF] Gateau | Real-time state estimation in a flight simulator using fNIRS[END_REF]. Two thirds of the crews committed at least one error and half of the crews experienced significant flight-path deviations. Importantly, such deviations appear to lead to numerous accidents observed during go-around [START_REF]Study of aeroplane state awareness during go-around[END_REF]. Particularly, the PM plays a crucial role for the monitoring of flight-path deviations [START_REF] Reynal | Pilot flying vs. Pilot monitoring during the approach phase: An eye-tracking study[END_REF]. In the next sections, we discuss the eye-tracking results that could support this hypothesis.

How did the PF and the PM Distribute Their Visual Attention During the Management of the Go-Around?

During the final approach, the PF's scanning behavior was consistent with that observed by [START_REF] Sarter | Pilots' monitoring strategies and performance on automated flight decks: An empirical study combining behavioral and eye-tracking data[END_REF]see Steelman et al., 2011 for detailed analysis) and [START_REF] Huettig | Mode awareness in amodern glass cockpit: Attention allocation to mode information[END_REF]. Importantly, we found changes in the pilots' scanning patterns during the go-around execution:

• Both pilots paid less attention to the OTW during go-around, looking outside less than 5% of the time. In contrast, they spent up to 40% looking outside during the final approach. This behavior is understandable because landing on the runway is no longer the objective. Pilots needed to redistribute their attention on the flight deck to control the go-around manoeuver. This finding is in line with previous studies that demonstrated that the OTW is mainly scanned during approach [START_REF] Huettig | Mode awareness in amodern glass cockpit: Attention allocation to mode information[END_REF][START_REF] Sarter | Pilots' monitoring strategies and performance on automated flight decks: An empirical study combining behavioral and eye-tracking data[END_REF]). • Airspeed scanning increased for both pilots. This is understandable due to the increased concern for stall at a potential high angle of attack and the need to retract the flaps with regard to specific speed values. • ND monitoring increased for both pilots. This behavior is consistent with the careful monitoring of the trajectory and potential incoming traffic.

In addition, there were important shifts in relative responsibility for the two pilots:

• The PF devoted more visual attention to AI monitoring than did the PM. This is logical because this instrument displays the flight director. Indeed, the PF had to follow the flight director to fly the selected path during go-around.

• The PM, shedding some visual attention for the two instruments above (AI and ND), greatly increased FCU scanning, involved with setting changing flight modes and targets.

In addition, the analysis of the explore/exploit ratio confirmed that the PF and PM used different ocular behaviors during the go-around. The PF was mainly in an exploit/focus mode, whereas the PM was in a more explore/monitoring mode. This finding is also consistent with the crew's attentional distribution during go-around. The PF looked mainly at three AOIs located in the primary flight display (PFD; speed, attitude and altitude indicators: 70%). This result confirms that the role of the PF is to "fly" the aircraft while controlling the flight path. In contrast, the PM's visual attention during the go-around is spread more broadly over the different AOIs, with briefer dwells mainly to check that parameters are within range. Taken together, these results confirmed that the PF and the PM used different scanning strategies according to their predefined roles.

Did the PF's and the PM's Visual Scan Ensure an Efficient Cross-Checking of the Flight Parameters?

The pilot-performance results emphasized that teamwork was not efficient for more than half of the crew during go-around execution because it led to error detection issues. How can we explain these deviations? Was this due to collective or individual "neglect" of specific AOIs? Is it possible to make a link between visual scanning behavior and overall crew performance? We might expect some differences here, based on the prior research of [START_REF] Wickens | Attentionsituation awareness (A-SA) model of pilot error[END_REF] that proficiency in traffic detection was related to individual differences in overall scanning, and of [START_REF] Bellenkes | Visual scanning and pilot expertise: The role of attentional flexibility and mental model development[END_REF] and [START_REF] Schriver | Expertise differences in attentional strategies related to pilot decision making[END_REF], who observed instrumentscanning differences related to pilot expertise. [START_REF] Lefrancois | The role of pilots' monitoring strategies in flight performance[END_REF] showed that gaze allocation of pilots who failed to stabilize their approach was suboptimal and more variable compared to the more proficient pilots.

Our statistical analyses disclosed that only one AOI clearly discriminated the six best from the six poorest performing crews: the AI. The poorer performing crews, particularly the PM, allocated significantly less attention to the AOI. Although none of the crews experienced aerodynamic stall during our experiment, the monitoring of the aircraft's energy state is critical and has been a contributing factor in several loss-of-control accidents during the go-around [START_REF]Study of aeroplane state awareness during go-around[END_REF]. This assumption is consistent with a recent eye-tracking study that revealed that PMs exhibited insufficient monitoring of speed during final approach [START_REF] Reynal | Pilot flying vs. Pilot monitoring during the approach phase: An eye-tracking study[END_REF]. Moreover, the analysis of the maximum time interval without a fixation on the relevant AOIs by the crew (see Figure 6) also appears to support this lack of monitoring. These qualitative results revealed that there were important lapses of time during which critical parameters such as the airspeed indication (12 s) or the altimeter (14 s) were not glanced at by any crew member. Keeping in mind that the mean time of the go-around execution was about 75 s, we could argue that any deviations of these parameters might remain unnoticed.

Eventually some explanations might be found in the PF's and the PM's visual strategies on specific AOIs. The individual eye-tracking analyses revealed that half of the PFs did not glance at the landing-gear indicator to verify that their PM effectively retracted it. In one case, the crew performed the go-around with the landing gear still lowered. More interestingly, four PFs out of six who deviated from the expected trajectory did not verify their PM's inputs. These PFs were following the flight director displayed on the AI. Two of these PFs (2 and 8) were particularly focused on the flight director to follow the flight path during the go-around. For instance, the PF 2 was so focused during 11 s on flying the flight director that he remained unaware that his PM had programmed an erroneous lateral flight path. Another noticeable illustration of such attentional issues occurred with PF 8, who focused for 22 s on the vertical flight path to capture the target altitude, to the detriment of the monitoring of the horizontal flight. This attentional fixation on one axis to the detriment of another has been identified as a causal factor of critical events during the approach phase (BEA, 2004a[START_REF]Serious incident at Nantes on 21 March 2004 to the MD-83 registered SU-BMF operated by Luxor Air[END_REF].

For their part, the PMs failed to detect their PFs' flight-path deviation in five cases out of six. PM 9 and 11 were highly focused on the flight-control panel for more than 12 and 15 s, respectively (see Figure 5) when their PF deviated. It is worth noting that all PMs spent a substantial amount of time (13.3%) interacting with the flight-control panel, entering the ATC instructions. In general, pilots are trained to glance at the PFD while entering the data in the flight-control panel but none of the PMs exhibited this expected behavior. Another task that captured the three other PMs' attention (2, 7 and 8) was the flaps management, which prevented them from monitoring the flight path. These suboptimal monitoring abilities exhibited by some PMs are consistent with a recent eye-tracking study that revealed that PMs exhibited inadequate scanning during final approach [START_REF] Reynal | Pilot flying vs. Pilot monitoring during the approach phase: An eye-tracking study[END_REF].

Conclusions

Our results confirmed that the go-around was a challenging task and that eye tracking provides valuable data to better understand pilots' performance. More interestingly, the qualitative and quantitative analyses of this study expanded the earlier findings from the ASAGA survey and accident analysis during go-around [START_REF]Study of aeroplane state awareness during go-around[END_REF]. Especially the eye-tracking measurements have highlighted several issues related to cockpit design and the monitoring of the flight parameters.

First, two user interfaces, namely the flight director (displayed in the AI) and the FCU have sometimes excessively captured respectively the PF's (see Table 1) and PM's visual attention (see Table 1 and Figure 3). Emphasis should be placed on training the PF to avoid excessive visual tunneling on the flight director, whereas the PM should be trained to interact with the FCU when flying low level; that is, checking the settings on the PFD while entering the data on the FCU.

Second, the eye-tracking measurements emphasized the essential role of the PM in the detection of flight-parameter deviations. The PM's numerous tasks (e.g., interaction with ATC, FCU settings, and flaps management) can leave this pilot ill equipped to face the sudden onsets of these actions and to monitor the flight path in the meantime. These results might appear surprising, as primary flight training emphasizes instrument scanning and cross-checking. Further studies are needed to confirm these findings as our sample size was small. It would also be relevant to manipulate other variables, such as round dial versus glass cockpit, low versus high level of automation, or experienced versus newly trained pilots, to disentangle all the variables that might affect visual scanning.

We believe that our results with those of others [START_REF] Lefrancois | The role of pilots' monitoring strategies in flight performance[END_REF][START_REF] Reynal | Pilot flying vs. Pilot monitoring during the approach phase: An eye-tracking study[END_REF]) support the recommendation made by the Federal Aviation Administration, stating that by March 2019, air carriers must include specific training to improve monitoring (see Flight Safety Foundation, 2014, p. 3). Specifically, our findings propose that training should emphasize the cross-monitoring of the primary flight parameters related to the energy state and the flight path of the airplane in demanding flight scenarios.

Figure 1 .

 1 Figure 1. An example of reference images and areas of interests (AOIs) for pilot flying (at left) and pilot monitoring (at right). We focused our analyses on the six AOIs that received the majority of scans: airspeed (AS), attitude indicator (AI), altitude indicator (ALT), navigation display (ND), flight control panel (flight control unit for Airbus and mode control panel for Boeing), and out of the window (OTW).

Figure 2 .

 2 Figure 2. Distribution of pilot flying's and pilot monioring's eye gaze on the six main areas of interest during the final approach (A) and the go-around (GA). AI = attitude indicator; OTW = out the window; AS = airspeed; ALT = altitude indicator; ND = navigation display; FCU = flight control unit.

Figure 3 .

 3 Figure 3. Mean explore/exploit ratios for pilot flying and pilot monitoring for final approach and go-around phases. Higher values indicate an increase of the explore mode, whereas lower values reflect an increase of the exploitation mode. Bars represent standard errors.

Figure 4 .

 4 Figure 4. Percentage of dwell time (%) on the airspeed indicator predict crews' differential performance during the go-around (poorer vs. best performing crews). Bars represent standard error.

Figure 5 .

 5 Figure 5. Ocular behavior of Pilot Monitoring No.11 during the go-around phase. Note that this pilot was excessively focused on the flight control unit (FCU) 15 s after the beginning of the go-around. MCP = mode control panel; MCDU = Multipurpose Control Display Unit; ECAM/EICAS = Electronic Centralized Aircraft Monitoring/Engine-Indicating and Crew-Alerting System; ND = navigation display; FMA = Flight Mode Annunciator; PFD = primary flight display.

Figure 6 .

 6 Figure 6. Maximum time between fixations on the four areas of interest (AOIs) related to the energy or the trajectory of the aircraft during the go-around. These are shown as boxplots with whiskers. The bold band represents the median values of maximum time interval without a fixation of either pilot flying or pilot monitoring according to the six main AOIs. The upper and lower ends of the boxes equals the 95% confidence interval. Whiskers represent ranges. AS = airspeed; AI = attitude indicator; ALT = altitude indicator; ND = navigation display.

Table 1 .

 1 Crews' performance related to visual scanning during go-around maneuver.

		Performance Errors	PF's Visual Cross-Checks	PM's Visual Cross-Checks
	Aircrew				Landing
	No.	PM	PF	FCU Settings	Gear	Go-Around Flight Path
	1	Landing gear not retracted None	☑	☐	☑
	2	Dialed an erroneous	eading deviation	☐	☑	☐Checked the FMA then shifted
		heading (240°) although	(40°)			to airspeed/flaps management
		he announced 340°H
	3	None	None	☑	☑	☑
	4	None	None	☑	☑	☑
	5	Heading mode not	None	☑	☑	☑
		correctly engaged
	6	None	None	☑	☑	☑
	7	Did not set the altitude on	Altitude exceeded	☑	☐	☐ Checked the flight path but
		the FCU	(500 ft)			quick shift to airspeed/flaps
						management when the altitude
						was about to be exceeded
	8	None	Heading deviation	☐Excessively	☑	☐Checked only vertical profile
			(25°)	focused on the		then shifted to airspeed/flaps
				vertical trajectory		management
				on the flight
				director
	9	Late setting of the altitude	Altitude exceeded	☐	☐	☐ Excessively focused on the FCU
		on the FCU	(600 ft)-activation			12 s
			of altitude alert
	10	Announced the vertical	Very late settings on	☑	☐	☑
		deviation-Altitude	the FCU
		exceeded (1,400 ft) and	(target altitude had
		activation of altitude alert	already been
			overshot)
	11	Did not engage the	Altitude exceeded	☐	☐	☐ Excessively focused on the FCU
		altitude properly	(200 ft), heading			15s
			deviation (20°)
	12	None	None	☑	☐	☑

Note. Checked box indicates that pilots (pilot monitoring [PM] or pilot flying [PF]) visually cross-checked each other's actions, whereas an empty box indicates they did not. Crews who experienced flight-path deviations are highlighted in gray. FCU = flight control unit; FMA = Flight Mode Annunciator.


Elsa Devienne

Comparing Exceptionalism in France and the USA A Transatlantic Approach to the Death Penalty Abolition Debate (1972-1977)

Introduction

"Sustained, systematic, organized, and relentless." As Denis Lacorne has recently pointed out, European media have unremittingly led the denunciation campaign of the death penalty in the United States throughout the 1990s and 2000s. France, in particular, has criticized the use of capital punishment in the American legal system resulting, ironically, in some American death-row inmates' life stories finding their ways into French newspapers more easily than into their American equivalents. 1 Numerous legal scholars and scientists have tried to theorize and decipher this "widening divide" between Europe and the "American exception." 2 However, the notion of exceptionalism does not take into account the recent transatlantic history of the abolition debate and effaces the period during which the purported exceptionalism was not American but French. 3 Although an "exception" repeatedly decried by its European neighbors for most of the 1970s, France has now removed capital punishment not only from its laws but also from its national "imaginary." 4 Historical scholarship on the history of the death penalty in France tends to reflect this obliviousness by emphasizing the inevitability of the 1981 abolition. 5 Similarly, collective memory tends to be excessively short regarding the guillotine: not so long ago, while the electric chair was collecting dust, the guillotine was still executing the condemned. In this article, I intend to look closely at the short period in the 1970s when American executions were halted while in France the executions continued in cases that were widely debated in public opinion. 6 By examining this intriguing moment in the transatlantic history of capital punishment, this essay follows a recent trend in the history of the death penalty. By erasing the traditional boundaries between national histories, it seeks to detect the rise of an "international judicial and political discourse on the penalty of death and its abolition." 7 The article focuses on the reception of the two major decisions taken by the Supreme Court in the 1970s and their direct consequences, as they were reported in the main French newspapers and television news magazines. 8 However, this essay is not solely about the French gaze on American practices. The journalists actively used American decisions to stoke the national debate by reading their meanings in light of the French context. While for a short period the United States occupied the position of exemplary "civilized" nation-thereby complicating the traditional scholarship on Franco-American relations largely preoccupied with anti-Americanism-this situation was soon reversed with the reinstatement of the death penalty in the US in 1976 and the Patrick Henry trial in 1977 that seemed to presage abolition in France. By tracing the progressive emergence of an official discourse on the death penalty as an aberration in French history, even before the actual law of 1981, the article demonstrates how French media gradually constructed the contemporary opposition between a death-penalty free France and a "barbaric" America. 9

II. The 1972 Supreme Court Decisions and their Reception in France

On June 29 1972, in a group of cases collectively called Furman v. Georgia, the Supreme Court declared every existing death penalty law in the United States unconstitutional on the grounds that they violated the "cruel and unusual punishment" clause of the Eighth Amendment. This decision, which effectively put a moratorium on capital punishment, was "one of the biggest surprises in its history" 10 and the result of a complex combination of factors. While Herbert

Haines emphasizes the "'inspirational' effect" of Supreme Court decisions in other arenas like Civil Rights, most scholars cite the constitutional attack on capital punishment led by the lawyers of the National Association for the Advancement of Colored People's Legal Defence Fund and the American Civil Liberties Union since the beginning of the 1960s. 11 That exact same day, a "few hours away" as Le Monde put it, French inmates Claude Buffet and Roger Bontems were condemned to death in one of the most controversial trials of the decade. 12 In 1971 while serving their sentence in the Clairvaux prison, the two inmates had taken a prison guard and a nurse hostage, and eventually killed them both. 13 As no execution had taken place in France since 1969, the sentence elicited a renewed interest in the abolition question. This historical coincidence, far from being ignored or dismissed as irrelevant to the national debate, forced French journalists in June 1972 to raise questions concerning the issue of the death penalty in a transatlantic, if not global, perspective. Significantly, the French media reported these two news items simultaneously, subsequently transforming their reportage into an opportunity to discuss the abolition debate from an international point of view. Most newspapers not only noted the coincidence and emphasized the significance of the two decisions on their front pages, but also broadened the perspective and defined the controversy in global terms. 14 In Le Figaro of June 30 1972, the coincidence was highlighted as follows: "At the same moment when the assizes court of Aube was condemning the two criminals to the death sentence, the Supreme Court decides that capital punishment cannot be applied." 15 According to La Croix, the French Catholic newspaper, "the coincidence cannot be missed" and the two events contributed "to put [ting] the death penalty on the agenda", while for Le Monde they "relaunch[ed] the controversy." 16 Both Le Monde and France Soir highlighted the symbolic value of the coincidence, and ran a special article on the international state of abolition. "The United States is joining the more than thirty countries in the world that have abolished the death penalty" announced Le Monde. 17 However, the abolition was not the only issue framed in global terms: the factors explaining strong public support for the death penalty-as exemplified by the applause and cheers at Buffet-Bontems' verdict-appeared to be the same in France and in the United States. Quoting the American pundit George Gallup's analysis of the American situation, the magazine Le Point identified the growth in criminality as the main reason for the increasing support for capital punishment in France. 18 According to some newspapers, the issue was not only international, it was also, on a more philosophical level, linked with a "civilizing process." 19 Le Figaro argued that the two events "relaunch [ed] this never-ending debate around this great and mysterious problem that has taken place in every civilized society." Similarly, La Croix was concerned by this "old and serious debate that no civilized society can evade," and elaborated the issue further: "Does the collectivity have the right to kill those who have transgressed the law?" 20 The notion of "civilization" was invoked in the death penalty debate as early as the late eighteenth century. It was used to promote moving executions to the jail yard, away from the public eye, as well as other methods of punishment that officials and reformers considered more "humane." Even proponents of the death penalty have invoked the discourse of "civilization" to argue for the compatibility of the ultimate punishment with the process of civilization. In contrast, used in connection with other concepts such as "humanization" and "progress," it has also allowed death penalty detractors to imagine and promote a teleological process towards abolition. [START_REF] Jurgen | Nineteenth-Century Executions as Performances of Law, Death, and Civilization[END_REF] The term thus needs to be historicized to cover how it evolved according to geographical and historical contexts. What defines "civilization" in these 1972 reports is the capacity for a society to at least broach the issue of the retention or abolition of the death penalty. All "civilized societies" are bound to confront this question. Nevertheless both Le Figaro and La Croix are both neutral on the issue of abolition (the French right, which Le Figaro represented, was divided on the topic, while the Catholic church had not yet taken a definite position). [START_REF]La loi et le bourreau: la peine de mort en débats (1870-1985[END_REF] They therefore did not embrace the discourse, especially prevalent after World War II, that identifies a civilized process leading inexorably to the rejection of legalized state killing. More cautious in their use of the phrase "civilized society", they simply acknowledged the shared conundrum present in American and French societies. 23 This more philosophical outlook adopted by both newspapers contributed to the international discourse on the penal system. While the French newspapers internationalized the issue, the immediate impact of the American abolition on the national debate in France was at the same time highlighted. During the 1970s, the French media played a central role in mobilising a major public debate on abolition. Partisans of abolition and their adversaries consistently discussed sensational cases through op-eds and opinion columns. 24 In this heated context, it is no surprise that the journalists used the Supreme Court decision as fodder to ignite the French debate. According to Le Monde, the coincidence "rejuvenate [d] the debate on the retention or the abolition of the death penalty in France." As the newspaper was largely in favor of abolition, the Supreme Court decision was exploited to strengthen the abolitionist side. The journalist argued that the question of abolition was posed in "identical terms in the United States" and that criminals "as revolting as Buffet and Bontems" like "Charles Manson and his accomplices" would serve their sentences in jail, just as the French criminals could in "the prison of Mende [START_REF]Mende is a French commune in the department of Lozère[END_REF] ." In other words, the same questions, the same arguments, and the same debate in both countries, should have begotten the same resolution: abolition. Hinting at Georges Pompidou's well-known repulsion for the death penalty, the journalist emphasized the coincidence by asserting that "what the Supreme Court has decided, Mr. Pompidou was ready to do just before the Clairvaux drama." 26 The newspaper was not only reporting information; it stressed the divergent path of the two countries, and the straight comparison tarnished France's image. Similarly, L'Express had reservations concerning the "preventive value of the ultimate punishment" in the case of Buffet and Bontems, both re-offenders: "Its exemplarity seems rather illusory. This is also the opinion of the American Supreme Court that has just abolished the death penalty." 27 The journalist hinted at one of the most cherished arguments used by the partisans of capital punishment: its purported deterrence effect. The Buffet and Bontems affair seemed to belie the efficiency of such an effect: they both knew that they could be executed if they were caught but they had decided to take the risk regardless. If the threat of the guillotine did not deter inmates from repeating their crimes, the journalist from L'Express implied, then the punishment seemed devoid of most of its legitimacy. The American Supreme Court was merely acknowledging this state of affairs by abolishing the death penalty. Becoming an integral part of the French debate, the American decision was even used by French journalists as a means to pressure the French president. Indeed, in Le Canard enchaîné, the American decision was one more argument for clemency-the exclusive domain of the president-being applied in the Buffet-Bontems case. The Canard addressed the article to President Pompidou: "You, the man of the last resort…What are you going to decide? Will you yield to the lynching mob or will you pardon the 'Enraged of Clairvaux'? Destiny is making it simple for you. In the United States of America where justice has never been easy on its criminals … the death penalty has just been abolished forever. If I were you, Mr. President, … I would take advantage of this example to order the Senate to put the guillotine away." 28 In contrast to La Croix and Le Figaro, the Canard was implicitly taking up the discourse that identifies "civilization" with the rejection of capital punishment. By equating the behavior of the public in the Buffet-Bontems trial with the irrationality of a "lynching mob", the newspaper's intent was to induce shame among officials, thereby influencing their choice. This tactic was not only adopted by journalists but also by famous abolitionists like lawyer Albert Naud. On June 29, as quoted by France Soir, Naud shouted out: "Great victory for the society indeed. Sending Claude Buffet to the guillotine! A man good for psychiatry!" He then emphasized the symbolic damage the decision imposed on the reputation of "Voltaire and Hugo's country." But above all, he asserted that "the height of shame for our country is that the sentence was pronounced the same day that the Supreme Court abolished the death penalty in the United States." 29 Naud exploited the lasting rivalry between France and the United States as to which country could claim to be the beacon of the free world. France, he implied, was losing ground. [START_REF]For a reflection on the "ethical war" between France and the United States, see Lacorne[END_REF]

III The US as Exemplary Nation

To stir up the feeling that France was taking the wrong path, French media represented the United States as an exemplary nation. Indeed, in the words of Le Canard it constituted "an example" that Pompidou should follow. This attitude strongly undermined the prevalent beliefs of the French public about the American penal system. Indeed, France-and for that matter European countries in general-have a long tradition of putting America "on trial" when it comes to its penal system. [START_REF] Temkin | The Sacco-Vanzetti Affair: America on Trial[END_REF] While the United State could pride themselves on having a far more gentle penal code than Europe in the nineteenth century, the situation was reversed in the twentieth. Starting in the 1920s with the Sacco and Vanzetti case, then followed by the Rosenbergs' death sentence and the execution of Caryl Chessman, Europe harshly criticized American use of capital punishment. [START_REF] Banner | The Death Penalty, 242-243. For an account of international reactions to the Sacco-Vanzetti affair, see Temkin, The Sacco-Vanzetti Affair[END_REF] However, the decision of 1972 seemed to turn the tables all over again. The sudden admiration for the American penal system was not only observable in right-wing newspapers, but also in the leftist ones as exemplified by the relatively positive depiction in Le Canard. The article in Le Monde reporting on abolition similarly ended with praise for the Court's ability to judge the issue not on criminological or penal grounds but as a philosophical question. "Do we still have to wait?" asked the journalist -"What gesture would indeed be less demagogic, more courageous, than the decision to put an end to what is not a sentence but a torture, not a penal sanction but a residue of barbarism?" 33 In this instance, while the United States was on the side of rationalism and humanitarianism, France was implicitly associated with backwardness and cruelty. As evidenced by many book titles ("The Anti-American Obsession", "The American Enemy"), the abundant scholarly literature on Franco-American relationships largely focuses on the phenomenon of anti-Americanism. 34 Nevertheless, this seemingly unexpected praise for American penal practices remains consistent with the paradoxical nature of French anti-Americanism. According to Denis Lacorne, the "discourses" that form anti-Americanism are characterized by "ambiguity and frequent contradictions." "Subject to frequent swings," they evolve depending on the immediate historical context. [START_REF] Lacorne | Anti-Americanism and Americanophobia: A French Perspective[END_REF] Negative opinions can also accommodate themselves with contemporaneous positive appreciations of the United States, as is patently clear in this case. While Le Canard exhorted Pompidou to imitate the American Supreme Court, it criticized in the same movement the American penal system by lampooning a justice so harsh towards its criminals "that there is the possibility sometimes of doing innocents in." [START_REF][END_REF] In addition, the general praise of the Court's decision did not win over all the media. L'Humanité, the French Communist party newspaper, dedicated a very short article to abolition and-although there was an article on the Buffet-Bontems case on the same pageno comparison was drawn between the two countries. While the Communist party was strongly opposed to the death penalty in 1972, the article denied the exemplarity of the American decision and asserted that actions were already taken to cancel the decision-a claim which was later revealed to be correct. 37 In the same manner, the 585 prisoners benefited only "in some way" from the decision, meaning, they were probably not going to be spared in the long run. [START_REF] Humanité | [END_REF] Far more preoccupied with the denunciation of the Vietnam war, l'Humanité refused to abandon its anti-Americanist discourse. Even if the United States appeared to be heading down the right path, it could not stand as an example for France to follow. The exception that confirmed the rule, L'Humanité remained distinct from the rest of the French media. The French reception of the 1972 Supreme Court decision evinced the rise of an international discourse on the death penalty's abolition. By conjuring up the notion of "civilization" or commenting on the American decision's exemplarity, the media refused to limit the debate to its national significance. Moreover, by not only reporting the news but also analyzing it as a portent of inevitable progress, a sign that the world was inexorably heading toward abolition, the journalists transformed the decision into a symbolic event that could have an impact on French politics.

IV The Reinstatement of the Death Penalty in the US

Surprisingly, the French media did not pay much attention to the American reinstatement of the death penalty. While the Supreme Court upheld the more rationalized sentencing procedure in a set of three 1976 decisions collectively known as Gregg v. Georgia, thereby reopening the door to the death chamber in America, Le Monde was the only newspaper to analyzeand strongly denounce-the decision. [START_REF] Banner | The Death Penalty[END_REF] If the national newspapers had regarded the United States as an example in 1972, this step back comforted the traditional French criticism toward the American penal system. Considering the consequences of the decision, Le Monde argued that "one should keep in mind the imponderable nature of American psychology … it is … obvious that the great majority of Americans still believe in the deterring and expiatory virtues of capital punishment despite the unceasing abolitionist campaigns." 40 Americans appeared widely influenced by rising crime rates and thereby supported a reinstatement of a harsh and severe penal system. The overall absence of reaction in the press could also be explained by the general abolitionist stance advocated by most national mainstream newspapers. A piece of information going against what was believed to be a world-wide trend toward abolitionism did not serve the cause well. In contrast to the 1972 decision, which journalists exploited to undermine the pro-death penalty cause, the 1976 decision went almost unnoticed, as if irrelevant in a French context that saw the number of executions declining. [START_REF]No execution had taken place in 1974 and 1975 as Valery Giscard d'Estaing had commuted most death[END_REF] Conversely, when Gary Gilmore-the first convict put to death in ten years in the United States-was executed in 1977 the French press showed a deep interest. Once again, a coincidence encouraged the journalists to adopt an international standpoint: three days after the Gilmore execution, the child-murderer Patrick Henry was condemned in France to life in prison, a momentous decision considering that public opinion was vehemently in favor of his execution. 42 The two events therefore inverted the previous situation: while France was "de facto abolishing the death penalty" as pointed out by L'Express, the United States reverted to their former practice. 43 The conditions were ripe for the setting up in the French media of a long-lasting opposition between a "barbaric" America and a reasoned France.

First, journalists once again exploited the Supreme Court's decision to inform the French abolition debate. However, this time the American reinstatement of the death penalty was not only used by the abolitionist side but also served as a strong argument in favor of retention. An anti-abolitionist law professor, Jean-Claude Soyer, took advantage of the simultaneous events to draw subtle comparisons between the two penal systems in a Le Figaro op-ed. Probing one by one the traditional arguments in favor of abolition, he denied the allegation that the death penalty is a more terrible "torture" than life imprisonment. To support his claim, he reminded his readers that "currently, in the United States, some inmates are struggling to obtain their executions." Although Soyer didn't explicitly name Gilmore, it was obvious to most readers that he alluded to the recently executed American. Indeed, Gilmore had not only refused the appeals filed by his lawyers to prevent his execution but also his last months in jail were disrupted by two attempted suicides. 44 Soyer then concluded his article: "We are right to believe in the efficiency of the death penalty, and therefore to retain its use as a weapon against crime …. Besides, French people are favoring it in a large majority (as do Californians, a people that it would be difficult to characterize as backward-looking)." [START_REF] Figaro | Soyer had already used the California situation to support the retentionist side shortly after the execution of Buffet and Bontems in an op[END_REF] Soyer was probably alluding to the November 1972 California referendum on "proposition 17" which intended to reinstate the death penalty, and which was accepted by a large margin. Building upon the reputation of California (and more generally, the United States) as a symbol of progress and innovation, Soyer hoped to avert the traditional abolitionist critique that equated the death penalty with barbaric societies. The allusion was discreet, but it demonstrated the argument's latent presence in French media discourse. L'Humanité was undoubtedly the newspaper that epitomized this opinion. Considered anachronistic in a civilized society, the death penalty was deemed a "medieval practice." In order to impress the readers and link the execution to an unfair and barbaric tradition, the journalist described Gilmore's last moments in terms of hunting: "Vile execution in the United States: Gary Gilmore was shot yesterday with a big game gun" yelled the headline. Although the method was chosen by Gilmore himself, the firing squad was represented as a shocking reversion to primitive times. Gilmore's body "collapsed like big game in the jungle" related the journalist. Interestingly, while the United States appeared as a backward country locked in the past, L'Humanité condemned its pervasive mass media as "experts in the art of [public] manipulation" as well as the execution's financial exploitation via filming, both symbolically corrupting the apparent characteristics of a modern and innovative nation. The ambiguous denunciation again addresses the paradoxical nature of anti-American discourses. For the journalist, there was no contradiction to ponder; the United States was a powerful country that lacked morality and judgment. Like Soyer, l'Humanité alluded to the commonalities of the French and American systems, and used the comparison to condemn both countries' practices. Examining American police accusations against the excessive clemency displayed by judges, the journalist cried out: "Mr. Poniatowski hasn't invented anything!" Michel Poniatowski, French minister of the interior and an avowed retentionist, had indeed recently taken a stand on the issue, advocating for the death penalty in the Henry case and supporting similar views held by the police officers union. [START_REF] Poniatowski | his opinion clear on the radio station RTL on February 19 1976[END_REF] The journalist also fustigated the "game of cat and mouse" present in the numerous deferments of Gilmore's execution. He asserted that binding the inmates' life to the stroke of a pen was very much like "the presidential power to pardon." 47 By hinting at the French system of pardon, the journalist effectively condemned the two systems in the same tirade. While in 1972 the communist newspaper was alone in its sharp criticism of the American penal system, it did not stand out among the French media in 1977. Journalists largely denounced Gilmore's execution and attached special attention to what seemed an outdated method of execution: the firing squad. Coined a "macabre soap opera" in the news, the Gilmore execution was scrutinized in its most graphic aspects, such as the fact that Gilmore had declined to wear the scarf over his eyes but was obliged to by the law. 48 Although Le Monde didn't indulge in the execution's gruesome details, the newspaper compared the death penalty to a "barbaric lottery" and denounced Gilmore's execution in 1977. 49 These reports bear witness of the revival of a French discourse censuring "barbaric" America. The guillotine was not yet put away in a museum. Nevertheless, the French national press was already undertaking the task of building a strong discourse against the death penalty. Indeed, in 1977-the last year that witnessed an execution in France-most of the media declared the impending abandonment of capital punishment. [START_REF]There were two executions in[END_REF] This was not a novelty: as early as 1972, several newspapers hinted at the coming disappearance of the infamous practice. Le Nouvel Observateur, sharply condemning the Buffet-Bontems death sentence, warned Pompidou that his failure to pardon the two criminals would "revive the death penalty he ha [d] de facto abolished since his arrival at the Elysée." [START_REF]Emphasis in the original[END_REF] Similarly, L'Express pointed out the fact that, according to abolitionists, if Pompidou granted clemency it "would mean the death of the death penalty." 52 Already hinted at in 1972, abolition had become more of a priority by 1977. Indeed, in most newspaper accounts, Patrick Henry's life imprisonment sentence amounted to an unofficial abolition. Echoing the words of one of Patrick Henry's lawyers, Robert Bocquillon, who, quoted in L'Express, solemnly declared the "de facto abolition of the death penalty in France," French media anticipated legal abolition. 53 Most symbolic was the title of the article that Le Monde ran on the event: "The death of a penalty?" If killing a child was not a capital crime anymore, reasoned the journalist, then the penalty was in serious danger of disappearance. Le Monde was not the only newspaper to run wordplays for the occasion: "Dead, the death penalty?" wondered Le Nouvel Observateur. While the journalist answered "not yet", he still emphasized the "great blow it just received." 54 This anticipation of the 1981 law, clearly present from 1972 onwards, might explain how a "broadly supported moral orthodoxy against the death penalty", as David Garland put it, was so firmly established shortly after the actual abolition. [START_REF] Zimring | The Executioner's Dissonant Song: On Capital Punishment and American Values[END_REF] As Evi Girling recently noted, few scholars have sought to understand the process through which the death penalty in Europe-and most spectacularly in France-"remains effectively beyond political will and imagination." [START_REF] Girling | European Identity[END_REF] In France, part of the reason seems to lie in the forceful denunciation that most French media engaged in throughout the 1970s.

V Conclusion

By gradually portraying France as a "de facto" death-penalty-free state, French media accustomed public opinion to the idea of an inevitable abolition. In the meantime, they developed a semi-official discourse that represented the guillotine as an aberration in French history. "Voltaire and Hugo's country" could no longer be associated with this infamous punishment. The American counter-example, starting in 1977, only helped in this process. As the "privileged Other of France," [START_REF] Guerlain | Miroirs transatlantiques: La France et les Etats-Unis entre passions et indifférences[END_REF] the country against which France had traditionally defined its identity, the United States allowed France to refine its distinctiveness around the death penalty issue. This resonates with David Garland's suggestion that scholars should attend to the "cultural role" of legal practices. Practices of punishment, asserts Garland, shape social meanings and social worlds and, by marking a difference between self and other, take on a symbolical dimension. [START_REF] Sarat | The Cultural Life of Capital Punishment: Responsibility and Representation in Dead Man Walking and Last Dance[END_REF] This remark is especially important within the framework of international rivalries as it demonstrates how foreign affairs can sometimes shape domestic policy. Legal scholar Richard Primus has shown how much American policy during the Cold War was influenced by the need to distinguish itself from the Soviet Union and Nazi Germany. [START_REF] Primus | A Brooding Omnipresence: Totalitarianism in Postwar Constitutional Thought[END_REF] Similarly, the American reinstatement of the death penalty reinforced French abolitionism. Starting in the mid-1970s, the death penalty therefore served as a cultural signifier for France to distinguish itself from the United States, thereby preserving and shaping its identity. While Evi Girling has dealt with this identity-building process in Europe, she has only concentrated on the 1990s and 2000s. [START_REF] Girling | European Identity[END_REF] Yet, to be accurate about the origins of the opposition between a death-penalty free Europe and a barbaric America, one should also take into account the 1970s. Although for a short period the United States embodied an example to follow, the reconstitution of a critical discourse toward the transatlantic neighbor was quickly undertaken following the Supreme Court's 1976 decision. In 1977, while Gilmore's execution inaugurated a new divide between the United States and Europe, the Henry trial ushered in the pervasive discourse on the "death of the death penalty." Anticipating the famous Mitterrand decision of 1981, French journalists played a major role in foreseeing and delineating the contours of a France free of its guillotine. In the meantime, they contributed to shaping an international discourse on penal practices and abolition that effaced geographical boundaries and encouraged a global appreciation of the significance of national decisions and events (particularly, of course, in America).

Cécile Toqué Pichon, L'abolition de la peine de mort en France. La " loi Badinter" (Paris: Panthéon, 2006) Jean Toulat, La peine de mort en question (Paris: Pygmalion, 1977) James Q. Whitman, Harsh Justice: Criminal Punishment and the Widening Divide between America and Europe (New York: Oxford University Press, 2003) Franklin E. Zimring (2003), Garland (2001) and Steiker (2002). For a critique of the notion of "exceptionalism" and a reflection on transnational history, see Thomas Bender, A Nation Among Nations: America's Place in World History (New York: Hill and Wang, 2006). 4 The death penalty was abolished in Italy in 1948, in Finland and Germany in 1949, in Austria in 1968, in the United Kingdom in 1969, in Sweden in 1972, and Le Figaro, Le Nouvel Observateur, L'Express, Le Point, La Croix, Le Canard Enchaîné, L'Humanité, France Soir, as well as the television news of channel 1 and 2. Clippings were also consulted from Minute, L'Aurore, Est Éclair, Le Petit Parisien, Libération-Champagne and Politique hebdo, available in Documentation Francaise, ed., L'abolition de la peine de mort (Paris: La Documentation Francaise, 1987). Most newspapers reviewed were either in favor of abolition or neutral. Some were adamantly retentionist (for instance Minute, politically on the far right) while others only showed support for the death penalty during the Buffet and Bontems case (the local press in particular). 9 Lacorne, "The Barbaric", 51. 10 Stuart Banner, The Death Penalty: An American History (Cambridge & London: Harvard University Press, 2002), 231. The quotation is from the New Republic. 11 The gradual decline in executions and the rise of abolitionist voices within and without the United States also played a role in the decision. See Herbert H. Haines, Against Capital Punishment: The Anti-Death Penalty Movement in America, 1972-1994 (New York & Oxford: Oxford University Press, 1996), 21. 12 Le Monde, July 1, 1972, 1. The French president, Georges Pompidou, had commuted all death sentences following his election in 1969. 13 Toqué Pichon, L'abolition, 62. 14 Le Monde ran on its front page two articles-one on the Supreme Court decision, the other on the combined analysis of the American situation and Buffet and Bontems' death sentences -under the same overarching title: "A Few Hours Away," Le Monde, July 1, 1972, 1. 15 Le Figaro, June 30, 1972, 1. 16 La Croix,July 1,1972,1;Le Monde,July 1,1972,1.


F Clerc

N Bertrand

B La Rocca

Taking multiple exposure into account can improve assessment of chemical risks

During work, operators may be exposed to several chemicals simultaneously. Most exposure assessment approaches only determine exposure levels for each substance individually. However, such individual-substance approaches may not correctly estimate the toxicity of "cocktails" of chemicals, as the toxicity of a cocktail may differ from the toxicity of substances on their own. This study presents an approach that can better take into account multiple exposure when assessing chemical risks. Almost 30,000 work situations, monitored between 2005 and 2014 and recorded in two French databases, were analysed using MiXie software. The algorithms employed in MiXie can identify toxicological classes associated with several substances, based on the additivity of the selected effects of each substance. The results of our retrospective analysis show that MiXie was able to identify almost 20% more potentially hazardous situations than identified using a single-substance approach. It therefore appears essential to review the ways in which multiple exposure is taken into account during risk assessment.

Introduction

Most workers are exposed to several substances in the workplace and the consideration of these complex situations in risk-assessment needs to be improved. Multiple exposure may result from simultaneous exposure to several chemical substances or from successive exposures leading to the simultaneous presence of these substances in the organism. The impacts of multiple exposure on worker's health is difficult to address and is therefore rarely taken into account in risk assessment.

Several risk-assessment methods have been proposed that rank the risks encountered in a singlesubstance approach [START_REF] Vincent | Méthodologie d'évaluation simplifiée du risque chimique : un outil d'aide à la décision[END_REF] [2] [3] [START_REF] Inrs | Seirich : évaluer le risque chimique[END_REF]. The results of these assessments can be used to establish priorities in the preventive actions to be implemented. When an assessment identifies specific risks, or if regulatory requirements demand it, atmospheric concentrations must be regularly measured to determine the levels of dangerous chemicals. When a work situation involves a number of substances, several separate measurement campaigns must be performed. The chemical risk is therefore assessed substance by substance, and does not take into account the combined toxicological effects of the cocktail of chemicals. Pending the availability of toxicological or epidemiological data on mixture effects, decision-making tools such as MiXie have been developed to evaluate these impacts.

In Canada, the Institut de recherche Robert-Sauvé en Santé et en sécurité du Travail (IRSST) and University of Montréal created the MiXie webpage in order to estimate the health-effects of cocktails of substances by applying a principle of additivity of effects [START_REF]MiXie : Les mélanges de substances en milieu de travail[END_REF] [START_REF] Fiala | Occupational health risk evaluation of exposure to mixtures of chemicals[END_REF]. MiXie can be used to identify potential toxicological effects by comparing the concentrations of the different substances to their individual OELV and then using this data to determine an exposure index for a particular cocktail of substances, termed the "Mixture" in Mixie. The Mixie software was recently adapted by the INRS for use with French OEL values [START_REF]MiXie France[END_REF].

In this study, the algorithms in the MiXie software were adapted for use with large datasets, such as data extracted from COLCHIC and SCOLA. The objective was to compare the results of riskassessments performed by single-and multiple-substance approaches.

Methods

2.1. Evaluation of the potential risks related to multiple exposure using MiXie software Given the high number of substances available on the market, it would be very difficult to determine the effects of all possible combinations of substances by performing experimental toxicology tests or epidemiological studies. MiXie, a decision-making tool available on the web, estimates the risk associated with exposure to several chemical substances, with the additivity of the effects as a hypothesis, supposing that substances causing the same harmful effects would additively increase the risks to workers. In MiXie, the effects identified for each substance are categorized into 32 toxicological classes, for example "central nervous system involvement", "liver involvement", or "embryonic or foetal disorders". For a given mixture, the toxicological classes shared by several chemical substances are highlighted and, for each common class, an exposure index is calculated (EI = exposure concentration measured / OELV). The MiXie algorithm is sensitive to the OELV adopted in each country as it uses the OELV to determine the exposure index for a mixture. Only effects appearing within five-times the OELV for studies in humans, and one-hundred-times the OELV for animal studies, are taken into account. The toxicological database for the Canadian version of MiXie contains over 700 substances, 347 of which have an OELV assigned to them in France. The toxicological classes defined in the MiXie algorithms are linked not to regulatory considerations, but instead to the scientific literature. Thus, the "cancer" class, for example, is associated with several substances in MiXie, some of which are not considered carcinogenic in CLP regulation [START_REF]European Parliament and of the Council, Regulation (EC) No 1272/2008 -classification, labelling and packaging of substances and mixtures[END_REF].

Extraction of measurement data and creation of "work situations"

All atmospheric concentration measurements made in line with regulations on French territory are, in principle, transmitted to the French Research and Safety Institute for the Prevention of Occupational Accidents and Diseases (INRS), where they are then entered into the SCOLA database [START_REF] Inrs | SCOLA[END_REF]. Likewise, all atmospheric concentration measurements conducted by the interregional chemical laboratories of the French regional health insurance funds or by INRS laboratories as part of preventive programmes, prospection, or support for epidemiological studies, are archived in the COLCHIC database [START_REF] Vincent | COLCHIC -Occupational Exposure to Chemical Agents Database: current content and development perspectives[END_REF]. The COLCHIC and SCOLA databases share a common technical structure and comparisons of exposure levels between the two databases are therefore possible [START_REF] Mater | Descriptive analysis and comparison of two French occupational exposure databases: COLCHIC and SCOLA[END_REF]. In addition, as the data are derived from different sources, there are no double-entries in the two databases.

For the period 1984-2017, the COLCHIC and SCOLA databases contain records of over 922,000 and 256,000 concentration measurements taken in over 26,000 and 7,300 companies, respectively. In both cases, the concentrations recorded in the database are associated with a chemical substance, a company, an activity sector and a task. This information is supplied using codes related either to specific reference data (e.g., the task performed by the operator) or to international references (the NACE code for the company' sector of activity. From all the data contained in the two databases, only individual samples corresponding to sampling durations of between 60 and 600 minutes were extracted. Moreover, only data recorded during a maximum of the last 10 years were retained (2005 -2014 for COLCHIC and 2007 -2014 for SCOLA). These data were grouped into so-called work situations, in which samples were collected in the same company, for the same working task and during the same month. For example, a work situation in company X might consist of 10 measurements of substance A, 5 measurements of substance B and 3 measurements of substance C, made during for the same task during the same month. The measurements for any given work situation are assumed to be representative of the exposure of a specific group of workers, performing the same task during the same period.

Assessing exposure for different situations

For each situation, maximum EI values (EI max ) were calculated for each substance. A representative situation is presented in Table 1. Three volatile organic compounds were sampled: toluene -3 measurements; methylethylcetone -2 measurements; and xylene -3 measurements.

Table 1. A representative multiple-exposure situation and the corresponding EI max calculations

For each class of toxicological effects triggered, the ∑EI value was obtained by summing the EI max values calculated for each individual substance in the mixture. The ∑EI values of our representative situation are listed in Table 2.

Table 2. Exposure index of the mixture (∑EI) calculated for each class of toxicological effect triggered

Results

3.1. Overview Of the 38,666 work situations identified in the two databases over the last decade, 13,629 were related to multiple exposures, i.e. situations in which workers were simultaneously exposed to at least two of the substances listed in MiXie. Among the 13,629 multiple exposure situations, 2,906 (21%) were considered "poorly controlled" for at least one class of toxicological effects according to the MiXie analysis. For some tasks, the proportion of "poorly controlled" situations relative to the total number of situations exceeded 15%, for example mixing (17%) and smelting (16%) (Table 3).

Table 3. Overview of work-situations in the COLCHIC and SCOLA databases for the period 2005-2014

The classes of toxicological effects involved in poorly controlled situations were most frequently eye involvement (16% of situations), upper respiratory tract involvement (16%), cancer (16%), skin disorders (14%), lower respiratory tract involvement (15%) and central nervous system involvement (7%). The other 26 classes together represented only 16% of situations. Details of the classes of effects activated in different situations are shown in Figure 1, where we observe, for example, that the "upper respiratory tract involvement" class was activated in 20% of machining situations.

Mixtures of substances

Using a Bayesian network [START_REF] Bayesialab | www.bayesia[END_REF] [13], 25 "typical mixtures", composed of between 2 and 5 substances, were identified. However, situations in which every substance contained in a typical mixture was sampled were rarely listed in the databases. For this reason, it is considered that a mixture was observed when at least half of the substances that comprise it were present. Thus, among the 2,906 "poorly controlled" situations, 6 mixtures were most frequently observed: these mixtures were encountered in over 3% of all situations (Table 4).

In Table 4, the frequency of observation of mixtures of substances in "poorly controlled" situations is shown for each task performed. Thus, the silica-related mixture composed of cristobalite, respirable dusts, quartz and tridymite was identified in 16% of the 623 poorly controlled machining situations activating at least one toxicological class. This particular silica-related mixture corresponds to a French regulatory definition. In some situations, several mixtures were observed and the sum of the values may therefore exceed 100% in a single situation, for example in the case of tasks performed as part of building and public works. For tasks related to substance mixing, the toxicity class "effects on the central nervous system" was activated in 12% of situations, compared to 5% on average for all tasks. Activation of this class correlated with the frequent and specific presence of mixture VOC-2 (2phenylpropene; butyl acrylate; acetone; methyl methacrylate; and styrene). It can also be seen that smelting tasks were frequently associated with effects on the lower airways: reported in 27% of situations where smelting is performed compared to only 17% of situations on average for all tasks. Table 4. Typical mixtures of substances, their toxicological effects and the frequency with which they were associated with various tasks (Frequency = the number of poorly controlled situations involving the mixture divided by the total number of poorly controlled situations).

3.3. Non-compliance with OELV Among the 13,629 multiple exposure situations, 2,906 "poorly controlled" situations were identified by the MiXie algorithms. Among these, 2,442 involved exposure of workers to at least one substance at a concentration exceeding its OELV. Therefore, 464 of the poorly controlled situations (i.e 16 %) would not have been identified on the basis of the OELV alone: no exposure values exceed OELV but the ∑EI was greater than 1. This is a false negative (Figure 2).

Figure 2. 16% of poorly controlled situations involved exposure of workers to mixtures at concentrations lower than the OELV of the individual components. These situations cannot be identified without the use of multiple-exposure risk assessment. In the table, "nb of situations" refers to the total number of work situations where the task was performed.

Most of the poorly controlled situations related to exposure to mixtures were associated with tasks in manufacturing industries-machining, preparation of surfaces, mixing and bottling-where the number of false negatives exceeded 20%. This is also the case for printing, textile, waste and steel working, though the number of situations here was smaller. The ratio of the number of poorly controlled situations, that cannot be identified from the OELV of single substances, to the total number of situations recorded in the databases helps to more clearly identify tasks associated with the highest risks due to multiple exposures.

Discussion

The multiple substance approach revealed 464 situations (i.e. 16 % of situations) in which no OELV was exceeded but where the ∑EI value was greater than 1 for one or more toxicological classes. These situations therefore pose potential health risks to the workers. A single substance approach, based only on the OELV of each substance, would not have identified any risk in these situations.

Although very useful, the MiXie algorithms have some deficiencies. Exposure to mixtures may give rise to a range of phenomena that may affect the toxicity of substances examined separately. The additivity of effects is the default hypothesis used in MiXie France. Infra-additivity refers to a situation in which the mixture is less toxic than the individual substances that comprise it. Finally, supra-additivity corresponds to a situation in which synergistic effects occur, meaning that the mixture is more toxic than the sum of the individual toxicities of the substances that comprise it. A more extensive analysis of the literature on mixtures will be necessary to identify all potential interactions between substances, instead of applying additivity in all cases.

The COLCHIC and SCOLA databases are not fully representative of all work-related exposure situations in France. For example, measurements in the databases were not collected by probabilistic sampling but were instead made for either insurance purposes (COLCHIC) or regulation purposes (SCOLA). The practices adopted by industrial hygienists may also differ, and thus when only one substance was sampled in a situation, there is no guarantee that this was the only substance present in the workplace. More likely, the industrial hygienist sampled only this particular substance because of insurance or regulatory contexts. Finally, not all of the substances present in the databases are listed in MiXie and, likewise, toxicological assessments are not available for all of the substances registered in the COLCHIC and SCOLA databases. Given all of these reasons, it is likely that the number of multiple exposure situations was underestimated in this study.

Despite this limitation, multiple exposure situations were frequently identified, representing 36% of all situations recorded during the last decade. Multiple exposure may represent more than half of all exposure situations in certain activities such as mixing, moulding, compression, synthesis, calendaring, and laminating, or in tasks performed in companies involved in smelting and printing. In MiXie, a "poorly controlled" situation is defined as a situation in which the EI of at least one class of toxicological effects exceeds 1. Most poorly controlled situations were identified on the basis of the OELV defined for individual substances. However, the tasks most frequently associated with exposure to mixtures of substances were also related to the most frequent observation of poorly controlled situations, and not all of these situations can be identified by single-substance approaches.

The challenge in risk-management is to identify hazards at the outset when defining the riskmanagement plan. Thus, in order to identify the hazards related to multiple exposure, it is important to obtain an exhaustive list of all chemicals present in the workplace. These could be components of products as well as substances emitted during procedures. To reduce the cost of sampling and analysis and to simplify sampling procedures in the field (limiting the number of active samplers placed on workers), new methods of multi-support sampling and analysis have been developed [START_REF] Guillemot | Identifying thermal breakdown products of thermoplastics[END_REF].

A qualitative analysis of possible effects should be performed with the help of software such as MiXie. This type of approach would make it possible to identify which mixtures of substances present in the workplace might contribute, through the additive potential of the effects selected, to the creation of a hazardous situation. In light of these results, it will now be possible to better target the substances that should be measured during a sampling campaign.

Conclusion

In this paper, work situations were analysed from the point of view of multiple exposures to chemicals. If only the OELV of individual components in a mixture are used in a risk assessment, almost 16% of potentially hazardous situations cannot be detected. With a multiple substance approach, several tasks, related to health, waste-treatment or mixing, are found to present higher risks. The chemical-cocktails most frequently associated with a higher risk were cocktails of powders linked to analysis of crystalline silica, mixtures of metals and mixtures of volatile organic compounds.

If multiple exposure is taken into account from the first stages of risk assessment, potentially harmful effects on workers' health could be greatly reduced. The approach used to identify chemical risks should include analysis of substances contained in products as well as those emitted during production procedures. Once all of the substances have been identified, an analysis of their potential effects on health should be performed using an approach such as that implemented in the MiXie software, which will allow the situations that pose the highest risk to workers' health to be highlighted.

Figure 1 .

 1 Figure 1. Toxicological classes activated in poorly controlled situations during different tasks.

Acknowledgements

We would especially like to thank the Canadian MiXie team for providing initial technical and scientific support: Marc Baril, Daniel Drolet, Naima El-Majidi, François Lemay, Claude Viau and Adolf Viskocil. We also thank the French INRS MiXie team for the OELV adaptation work and for their involvement in the future phases of the project: Stéphane Binet, Pierre Campo, Laureline Coates, Michel Falcy and Florence Pillière. Gautier Mater is thanked for providing the COLCHIC and SCOLA exposure data. Alice Wiiliams is thanked for English translation.