Pierre Larrivée
email: pierre.larrivee@unicaen.fr

Turning negative: Micro-steps from Negative Polarity Item to Negative-Word

Keywords: NPIs, n-words, diachronic evolution, grammaticalization cline, Finnish, French, English, Italian, vulgar minimizers NPIs, n-words, diachronic evolution, grammaticalization cline, Finnish, French, English, Italian, vulgar minimizers

This paper revisits the debate as to whether n-words such as English nobody, French personne and Italian nessuno are indefinites or intrinsically negative. Intrinsic negative value is diagnozed by use in the three contexts of fragment answers, double negation and constituent negation. Are these criterial contexts involved in a predictable way through the development of future n-words? The question is answered by a detailed study of Polarity Sensitive Items (PSI) that are potentially ambiguous between n-word and negative polarity item (NPI) in four different languages (Finnish, French, American English and Italian). An ordered relation is found from negative fragment answers, that can be evoked by strong NPIs, to double negation and constituent negation, that are communicated by intrinsically negative n-words. Having identified micro-steps into n-word status, the paper demonstrates that n-words are not mere indefinites, and must have an intrinsic negative value.

Introduction

Since the 1970's, a debate has been raging as to the nature of n-words1 such as English nobody on the one hand and French personne and Italian nessuno on the other. The debate bears on whether such n-words are i. indefinites that inherit their negative value from the clausal context, ii. intrinsically negative expressions that enter concord relations, or iii. ambiguous between the two (see [START_REF] Giannakidou | The Landscape of Negative Dependencies: Negative Concord and N-Words[END_REF] and references therein 2 ). The options arise from the contrasts provided by the following illustrations. Referring to the standard variety of each language, use of two negatives with a single clausal negative interpretation is excluded in (standard) English ( 4), but allowed in French and Italian. This distinction has led some to suspect that the latter are of a different kind from the former, and pattern like Negative Polarity Items (NPIs)3 such as anybody. Furthermore, whereas a postverbal negative is legitimate in English (7), it needs licensing by a preverbal one in Italian (compare ( 6) and ( 9)), much like NPIs would. From the perspective of English, it would be tempting to say that Romance n-words are not the real negative thing, but only some kind of indefinites.

However, negative status is suggested by at least three diagnoses4 identified in the literature (e.g. [START_REF] Larrivée | Is there a Jespersen cycle[END_REF]). These are fragment answers, double negation and constituent negation. A fragment answer with a negative reading can be expressed by the three identified n-words, (10) -Who got the virus?

-No one. (11) -Qui a eu le virus ? -Personne. (12) -Chi ha avuto il virus ? -Nessuno. and could not be by a NPI like anything. This would suggest that the item is the sole locus of the negative reading. Giannakidou argues that the negative reading comes not from the item itself, but from the elided negative marker that would become visible if the full sentence were restored (e.g. the preverbal ne that would be found in the full answer Personne n'a eu le virus in ( 11)) (see Weir 2020; Moscati 2010: 100ff for a general discussion of the technicalities of negative elision; for data from Hungarian supporting Giannakidou, see [START_REF] Puskas | Negative licensing contexts and the role of n-words[END_REF]. However, no such negative marker is found with the Italian preverbal n-word in (12). 5 Likewise for the Arabic negative determiner wala, meaning that nothing else can account for its negative value as noted by Lucas (2009: 210). Also, if elided negative material could license the fragment answer, then such an answer could contain a NPI expressing negation on its own (Iordachioai 2009: 91), and no such NPI fragment answers are found. If an elided negation could influence the interpretation of an answer, this should be possible in any fragment answer, and it is not: the response "-A snake" to "-What did you see?" never means "I didn't see a snake" [START_REF] Watanabe | The genesis of Negative Concord[END_REF]). The balance of argument is therefore in favor of intrinsic negative value (see also [START_REF] Espinal | Interpreting argumental n-words as answers to negative whquestions[END_REF]. The conclusion may not be so clear in other fragment contexts such as coordination, gapping, participial constructions and comparatives [START_REF] Herdan | Licensing Negative Fragments and the Interpretation of Comparison Pascual José Masullo[END_REF], Iordachioaia 2009: 237ff). Comparatives for instance allow both negative and indefinite readings of n-words [START_REF] Lucas | The development of negation in Arabic and Afro-Asiatic[END_REF].

(13) It's better than nothing. (Having this is better than having nothing.) (14) It's better than nothing before. (This is better than any other thing we've seen before.) Double negation has early on been identified as an environment which argues in favor of negative status of n-words. In the following elicitations:

(15) Nobody "did nothing". (= Everybody did something) (16) Personne "n'a rien fait". (17) Nessuno "non ha fatto niente". the double negation must come from each of the two n-words (among others, Larrivée 1995[START_REF] Puskas | Negative licensing contexts and the role of n-words[END_REF][START_REF] Ovalle | Double negatives, Negative Concord and metalinguistic negation[END_REF], Mathieu 2004[START_REF] Baunaz | French n-words: Against an indefinite analysis of personne[END_REF], Iordachioaia 2009: 94-96). The argument is strengthened when the double negative reading is induced by a fragment answer [START_REF] Espinal | Interpreting argumental n-words as answers to negative whquestions[END_REF][START_REF] Garzonio | Negative Concord in Russian: An Overview[END_REF]).

(18) -So, who did nothing?

-Well, no one really. (= Everybody did something)

Fălăuș & Nicolae (2016) suggest that this may be due to the fact that as strong NPIs, the relevant Romanian n-words in double negation configurations can license a negative. This of course is equivalent to saying the n-words have an intrinsic negative value.

Finally, an intrinsic negative value can be argued for with constituent negation uses. The term is used here6 to refer to the local scope of a negative, that does not bear on the predicate [START_REF] Haegeman | Negative preposing negative inversion, and the split CP[END_REF][START_REF] Kato | Interpretative asymmetries of negation[END_REF][START_REF] Collins | Classical NEG Raising[END_REF]. A traditional illustration going all the way back to [START_REF] Klima | Negation in English[END_REF] is Mary would be happy with no job: putting aside the clausal scope interpretation in which Mary is not happy whatever the job, the constituent scope induces the reading where Mary would be quite happy even if she had no job. Typical contexts of constituent scope are provided by the following illustrations.

(19) a.

He is working for nothing. (= in vain) b.

I'm left with nothing. c.

They're fighting about nothing. d.

It is destroyed to nothing.

Patently, the negative reading of the n-word cannot be blamed on a clausal marker, since concord with a clausal marker is impossible for a constituent scope negative. Constituent scope is sometimes dismissed as relating to formulaic expressions [START_REF] Svenonius | Strains of negation in Norwegian[END_REF][START_REF] Clercq | A unified syntax of negation[END_REF]: 142, Franco, Kellert, Mensching & Poletto 2016), which does not explain why it would be available across languages. Penka (2001) suggests that the n-word remains licensed by a covert operator situated inside the prepositional phrase, but this is a stipulational move -if such an operator were available, it should allow NPIs (such as He is working for anything with the same reading as nothing), which are not found. Constituent negation is thus a significant problem for an indefinite approach of n-words [START_REF] Déprez | A lexicalist account of negation and negative concord in Mauritian[END_REF].

Other behaviors separating n-words from NPIs have to do with position. In languages like English, French and Italian, NPIs cannot normally precede the negative that licenses them, as illustrated by the following. Let us consider these criterial contexts in a comparative perspective. We know that diachronically, many n-words were previously NPIs: In the medieval period, personne 'nobody' was an indefinite comparable to anybody (Larrivée & Kallel 2020 and references therein). We know that the evolution into the former from the latter relates to use in a bridging context, an environment where items are ambiguous between two readings that therefore allow reanalysis with the new interpretation [START_REF] Heine | On the role of context in grammaticalization[END_REF]. The bridging context from NPI to n-word is strong polarity environments (in the (in)direct dependence of a clausal negation or without): [START_REF] Larrivée | The empirical reality of bridging contexts. Strong polarity contexts as the transition between NPIs and n-words[END_REF] show that this is the context where French NPIs are distributed at notable rates (over 50% in their corpus) just before acquiring a majority of n-word uses. According to [START_REF] Heine | On the role of context in grammaticalization[END_REF], the acquisition of the new reading is actuated by occurrence in switch contexts, that are compatible only with the new interpretation. Whether such switch contexts are represented by fragment answer, double negation and constituent negation is a question that arises. A further question is whether there is any ordering between these criterial contexts. In the same way that there is an ordered passage from weak NPIs to strong NPIs to nwords, one could imagine that this transition is structured by micro-steps e.g. from use in fragment answers, to double negation, and then constituent negation. These questions are examined in this paper, which is organized in the following way. First, we look at one series of Polarity Sensitive Items (PSI)7 in Finnish, that look very much like NPIs, and investigate how native speakers react when confronted with uses of PSIs from other languages in the presumed switch contexts. Second, the effective diachronic evolution of one strong NPI in French is examined, showing that not all criterial uses are available to all items, implying an ordered pathway. Finally, the full pathway is illustrated by (some of the) rude PSIs in contemporary American English and Italian. The conclusion is that PSIs used in the criterial contexts must be analyzed as bearing their own negative value at least in these contexts, which are precisely the contexts responsible for the historical acquisition of n-word status.

A PSI set in Finnish

Finnish is famous for marking clausal negation via a specialized verb [START_REF] Miestamo | A typological perspective on negation in Finnish dialects[END_REF]Vilkuna 2015: 458, her Polarity Sensitive Items divide into three paradigms according to Haspelmath (1997: 292ff).

The "mainly negative" one is formed with the interrogative augmented with kaan glossed as "not even". It therefore fits squarely into the category of Polarity Sensitive Items formed on a wh, as in Hindi, Japanese and Korean [START_REF] Cheng | The non-uniformity of wh-indeterminates with free choice and polarity in Chinese[END_REF][START_REF] Giannakidou | In)Definiteness, polarity, and the role of whmorphology in Free Choice[END_REF]. Representative item mittä-än 'nothing' is found with negation and n-words, in comparatives, in conditionals and under the command of lexical negatives (Haspelmath 1997: 294).

( The general situation should mean that negative uses are unavailable 8 for these PSI in Finnish.

To explore this expectation, a translation experiment was set. Twelve advanced Finnish learners of French were asked to translate ten French sentences without any further instruction. Two sentences -3., 8.-had a polarity use with a direct equivalent in Finnish. Eight however 8 In the standard register. There are however contemporary uses in vernacular registers where these items are used without an antecedent licensor [START_REF] Kotilainen | Konstruktioiden dynamiikkaa[END_REF] at all.' Though it seems tempting to analyze the indefinites as negative here, this example of the so-called "aggressive mood", which is restricted to substandard Finnish and to specific emphatic contexts, is probably comparable to utterances like the English "The hell I will!"" (2015: ft 16). On these rude expressions, more below. represented the criterial negative contexts -fragment answer in 1., 5. and 6., double negation in 4. and 10., and constituent negation in 2., 7. and 9. -that are not available in Finnish.

1. -Qu'est-ce que tu as fait finalement pour ton anniversaire ? -Rien du tout.

-What did you do for your birthday? -Nothing at all. 2. Je le surprends souvent en train de parler à personne. I often surprise him speaking to nobody. 3. Si jamais tu retrouves ce roman, dis-le-moi If ever you find this novel again, tell me. 4. Proust n'a pas rien écrit sur le souvenir, voyons ! Come on! Proust didn't write nothing about memory ! 5. -Qui est-ce que tu as vu le week-end dernier ? -A peu près personne.

-Who did you see masy week-end? -Practically nobody. 6. -Où est-ce que Luc va pour ses vacances ? -Nulle part, il reste à la maison.

-Where is Luke going for his holidays? Nowhere, he's staying at home. 7. Ecoute, franchement, tu travailles pour rien. Listen, frankly, you're working for nothing. 8. Elle était plus heureuse cet été-là qu'à aucun moment de sa vie. She was happier that summer than at any moment in her life. 9. Luc habite au milieu de nulle part. Luke lives in the middle of nowhere. 10. Jamais Modiano n'a rien écrit, il a toujours maintenu une activité littéraire. Never has Modiano written nothing, he has always maintained a literary activity.

Contexts unavailable to Finnish PSIs should be problematic for the informants. And indeed they were. The polarity uses in 8. and 3. presented no difficulties, and the fragment answers in 1., 5. and 6. were as expected translated with a negative verb. More revealing were the constituent uses and double negation cases. The constituent uses gave way to avoidance of the PSI, where "talking to no one" in 2. was translated by "talking to himself" and "talking alone", with 2 metalinguistic comments indicating that a PSI couldn't be used; and "working for nothing" in 7. translated as "unnecessary". Such avoidance manifested itself for 9. in the answer of 1 informant who suggested "in the wilderness" for "in the middle of nowhere", which however due to influence from English has a literal translation "keskellä ei-mittään" used by all other informants. The double negation cases in 4. and 10. gave way to two translations and one metalinguistic comment indicating a Negative Concord reading of the original; of those who understood the double negation reading, 3 offered metalinguistic comments regarding the difficulty to translate, 2 others avoided "nothing" altogether, 1 transformed "write nothing" by unambiguously local scope expression "without writing", and 5 directly provided the positive version of (4) (for a similar strategy of producing the equivalent positive sentence in double negative contexts, see [START_REF] Li | Mismatches in the interpretation of isolated negative expressions in Mandarin Chinese[END_REF].

The situation of PSIs in the standard register of Finnish is that they are essentially NPIs. The translation experiment set here shows that criterial contexts of double negation and constituent negation that indicate intrinsically negative PSIs cause considerable problems to informants. Therefore, there is a qualitative difference between double negation and constituent negation on the one hand, and fragment answers on the other. Fragment answers are not available for PSI on their own in the standard registers, but there are indications (see footnote 8) that such a use is developing. In the next section, another instance of a qualitative difference between these contexts is illustrated by the diachronic evolution of a further PSI.

A strong NPI in French

English at all is a straight Negative Polarity Item. Its distribution comprises a fair few of the standard contexts listed in [START_REF] Giannakidou | Polarity sensitivity as (non)veridical dependency[END_REF] So unlike English at all that is available in some of the weak (( 33)-( 43)) and in the strong (( 31)-( 32)) polarity contexts, it is in strong polarity contexts that French du tout is found [START_REF] Burnett | An Extra-Strong NPI? Pantoute in Québec French[END_REF], and in fact only in a subset of those will do: that is, the direct scope of without or a clause-mate negator, to the exclusion of their indirect scope.

( The strong NPI goes one step further than other NPIs, strong or otherwise, in that it can introduce negation on its own in a fragment answer, at least in contemporary literary French [START_REF] Detges | Grammaticalization vs. Reanalysis: a Semantic-Pragmatic account of functional change in Grammar[END_REF]: 187, Detges 2003, van der Auwera et van Alsenoy 2016, among others). Thus, in the following :

(61) -A-t-il travaillé? -(Pas) du tout.

the answer is a negative, even without a clausal negator. As far as I know, this is not available in English.

(62) -Did he work? -*(Not) at all.

However, as with English at all, du tout does not on its own lead to double negation readings.

The following never mean that someone has always had work, unlike with a clausal negative such as Never has he not worked at all. Thus, du tout is a strong polarity item that has a fragment answer use typical of n-words. This is not purely idiosyncratic: the Quebec French equivalent pantoute has the same behavior, and so do items in other Romance languages -such as de loc in Romanian [START_REF] Cristescu | Actele celui de al XV-lea Colocviu Internaţional al Departamentului de Lingvistică: Perspective comparative şi diacronice asupra limbii române[END_REF]). These fit the diachronic pattern identified by [START_REF] Larrivée | The empirical reality of bridging contexts. Strong polarity contexts as the transition between NPIs and n-words[END_REF] following which items that are to be n-words have a majority of strong polarity uses.

Whether such a pattern applies to du tout is investigated here. The data used is from the literary database Frantext, because of the abundance of the material that it offers over several centuries. The expectation was that if it follows the pattern of other NPIs, du tout would initially be found mostly in weak polarity contexts, then in strong ones, before the first negative uses in fragment answers arise.

All occurrences were extracted for the period from the 16 th century to the present. The first 100 occurrences at the beginning of each 50 year period from 1550 was manually examined for reading. A further 100 occurrences was later considered from 1625, as it seemed to be the point of change. The examination revealed four main cases, and a few irrelevant sequences where "du tout" reflects a string other than the polarity expression (below, "tout" is a modifier of the following noun, not relating directly to "du") (67) L' ange du tout-puissant (1656) The angel of-the all-powerful A literal reading 'of the whole' is attested occasionally throughout the corpus.

(68) le commencement est la moytié du tout (1552) the beginning be-PT-3PS the half of-the all The beginning is half of the whole

The one that is most represented in the earlier period is the high degree reading (also found as a precursor use of English at all, Horn 2001b: 182) (69) je cuide les autres du tout insensez (1553) 1PS-NOM believe-PR-1PS the-PL other-PL of-the all senseless I believe others to be completely senseless It tends to co-occur with items of a lexical negative polarity, as senseless in the example above. The weak polarity contexts are in fact exceedingly rare. ( 70 The number of occurrences of the four uses per period is provided in the table below, which also gives the number of cases ambiguous between the literal and high degree readings, and that of other, irrelevant occurrences. The historical evolution therefore goes from a majority of positive high degree uses until 1625, shifting to a majority of strong negative polarity uses from 1650. 9 The strong polarity context is mostly with an antecedent clause-mate clausal negator, and there is an overrepresentation of emphatic point 'not at all', as in example (72): 3 in 1550, 17 in 1625, 34 in 1650, 46 in 1700, 55 in 1750 and 23 in 1800. This suggests that an emphatic reading may relate to NPIs specialized in strong polarity contexts, as suggested by [START_REF] Giannakidou | The dynamics of change in Dutch enig: From nonveridicality to strong negative polarity[END_REF].

Literal

The point of this investigation was to establish whether there is a detectable pattern of evolution leading to use as fragment answer on the part of a PSI. The first occurrences of the item in a fragment negative answer is in 1807.

(73) -Vous n'avez pas été tenté d'apprendre l'italien ? interrompit Oswald.

-Non, du tout, reprit le comte d'Erfeuil, cela n' entrait pas dans le plan de mes études.

(Stael, 1807, Corinne ou l'Italie) -You weren't tempted to learn Italian? Oswald said, interrupting -No, at all, continued the Earl of Erfeuil, this did not figure in my study plan.

Fragment answers thus appear when the NPI has a majority of uses in strong polarity environments. This suggest that usage in strong polarity contexts is a condition to expressing negative fragment answers. Such fragment answers are qualitatively different from either double negation or constituent uses, which are not available for the studied item. Thus, negative fragment answers would be the first step on the way to acquiring n-word status. With this in mind, we move to the next section, to discuss items that have a larger range of criterial uses.

9 One expectation that is however contradicted by results is that there is but very few occurrences of du tout in weak polarity environments. These occurrences are mostly at the beginning of the development, and essentially disappear once the expression has a majority of its uses in strong polarity contexts. Why there is no early period with a substantial proportion of weak polarity uses may be related to the degree adverbial origins of du tout.

American and Italian rude PSIs

It has been noted that in the relevant registers, English has various rude expressions10 that function as PSIs. American English11 expressions listed by Postal (2004: 159) are beans, crap, dick, didley, didley-poo, didley-squat, fuck-all, jack, jack-shit, jack-squat, piss-all, poo, shit, shit-all and squat. Interestingly for our purpose, these "vulgar minimizers"12 display dual behavior13 of NPIs and n-words.

( To account for this, the representation of items in Type Z uses is proposed to depart from that of n-words. Inspiration is drawn from Déprez for whom fully negative items result from the lexical element raising to a high position in the DP [START_REF] Déprez | Parallel (a)symmetries and the internal structure of n-words[END_REF] which is left empty by NPIs in which the lexical element is lower down in the structure. It is proposed that vulgar minimizers are headed by a non-realized determiner "zero". Thus, squat would be represented as [DP [zero] + [N squat]]. This view seems essentially supported by De [START_REF] Clercq | Squat, zero and no/nothing: Syntactic negation vs. Semantic negation[END_REF], for whom the vulgar minimizers pattern with the semantic negation expressed by "zero" rather than with a n-word. The reader can verify that zero and squat are equally problematic in the following. ( 83 If the difference between squat and nothing hangs on the determiner position being filled by a covert zero element, then the expectation is for the position to remain unrealized. Postal points out that a sequence such as * He knows no squat about Botswana is ungrammatical. Unsurprisingly, this correlation does not necessarily extend to other languages. Italian vulgar minimizers displays a similar duality to the English ones [START_REF] Floricic | Un cazzo, un cavolo, un cacchio, un corno, un tubo, ecc. come termini din polarità negativa ? MS[END_REF], Giorgi & Poletto 2019) 14 These two studies also report structures such as the following. a. Cosa cazzo / diavolo / *tubo fai? What the fuck are you doing? There seems to be a disjunction between rude expressions adjoined to a wh and those used as PSIs. There is no article in the former; and the article in equivalent contexts in English (What the fuck does he know?) is not legitimate in PSI uses (He knows (* the) shit).

The cross-linguistic representation of rude expressions adjoined to wh appears significant. A vivid Polish illustration is cited by [START_REF] Kehayov | Taboo intensifiers as polarity items: Evidence from Estonian[END_REF]. b.

On myśl-i, Ŝe jest chuj wie jak mądry. he think-3SG that be.3SG dick know.3SG how smart 'He thinks he is so smart (lit. 'He thinks he is dick knows how smart'). See the work by den Dikken & [START_REF] Den Dikken | From Hell to Polarity: "Aggressively Non-D-Linked" Wh-Phrases as Polarity Items[END_REF].

The determiner position is thus unavailable for a covert operator. Minimally, Italian vulgar minimizers cannot be represented as American English ones.

The identified duality of uses is related by Horn (2001b) to the general evolution of negation, from a licensed NPI to a n-word used without concord. The evolution does not necessarily affect every item at the same pace. It might be that the distinction between n-word and vulgar minimizers as diagnosed on the basis of the behavior of squat only applies to squat but not to other items. This is what a quick look at the usage as reported by the Corpus of Contemporary American English demonstrates. Leaving aside highly polysemous items such as dick (35498 occurrences) and jack (94 037), and qualitative cases such as the following (98) Spain's Treasury held a bond auction -and fuck-all was it nasty: (99) it was a fuck-all of a day, mike. (100) And everything went shit-all from there (101) Ain't never seen anyone so shit-all stupid as you driving off that road. the uses as Type A or Type Z of various items 15 The last two categories point out to the difference between fuck-all and squat. The former precedes the verb, a use that characterizes n-words; it is normally not found with NPIs, and indeed it is not attested with the latter item. Fuck-all has a preponderance of Type Z, n-word uses. Squat has a clear majority of Type A, NPI-like uses. The proportion of fragment uses of fuck-all is more than twice as much as with squat. This latter item is attested in the subordinate of a negative main-clause, which is only available for NPIs and excluded for n-words.

(137) Don't pretend for a second that conserves or pubs give SQUAT about those Americans that were killed anymore than you accuse dems of not caring.

The suggestion is therefore that the lack of parallelism between Type Z and n-word nothing is actually due to the fact that squat is simply less advanced than fuck-all on the way to negative status. Let us run the items through the tests that we have used before, fragment answer, double negation and constituent negation. Fragment answers are displayed by the three surveyed items with more than ten occurrences (fuck-all, jackshit, squat). Double negation is more contentious. Postal finds that unlike nothing, squat does not yield a double negation interpretation in the following. However, the following elicitations seem acceptable to the various native speakers that I have consulted.

(147) -The problem is you did squat / fuck all.

-I did NOT do ?squat / fuck all. (148) -Jane understands squat / fuck all about drones.

-Come on now, Jane may not be the brightest crayon in the box, but she doesn't "understand squat / fuck all".

As before, we find that in this context, fuck-all is better accepted than squat. Finally, regarding constituent uses, they are well attested with both items, although fuck-all seems more frequent.

(149) a. I'm left with fuck all in the end. b.

They are both working for fuck all at the moment c.

Dr. Girlfriend and Dr. Sodbury have been fighting about fuck all (150) a.

I'm left with squat in the end. b.

They are both working for squat at the moment c.

Dr. Girlfriend and Dr. Sodbury have been fighting about squat A greater range of negative uses is communicated by fuck-all than by squat, suggesting a closer parallelism between (some of the) rude PSIs and straight n-words than has been initially envisaged.

What with the Italian versions? The same variation in range is displayed between items. Whereas cazzo is generally accepted in all criterial contexts, tubo may or may not, and piffero tends to be rejected. Fragment negative answers are acceptable for all, and double negation as well as constituent negation induce more restrictions. There are variance in the judgement of speakers especially where double negation in concerned, but this may well be due to the markedness of the configuration [START_REF] Larrivée | The markedness of double negation[END_REF]. In any case, the view that cazzo is the more advanced term of the paradigm (« quello il cui grado di grammaticalizzazione è più avanzato."), as per [START_REF] Floricic | Un cazzo, un cavolo, un cacchio, un corno, un tubo, ecc. come termini din polarità negativa ? MS[END_REF], seems correct. 16The exploration of vulgar minimizers was here conducted on synchronic data -a diachronic investigation being difficult for the obvious sociolinguistic reason that strong taboo expressions are unlikely to make it in print before the 1970s, as proved by a perusal of the Corpus of Historical American English. The English and Italian items nonetheless support the pathway of variation and change observed in the previous sections. First, use as fragment answer is accessible to vulgar minimizers because they have a notable proportion of uses in strong polarity contexts. Second, only minimizers that have a majority of n-word uses such as fuck-all and possibly cazzo communicate double negation and constituent negation in a more generally accepted way. The consequence of these observations in relation to those in previous sections is articulated in the conclusive discussion below.

Conclusive discussion: so what?

This article identifies diagnostics that determine when Polarity Sensitive Items are of the NPI or of the n-word type. Arguments are further provided that n-word PSIs have an intrinsically negative value, as shown by the ability to communicate negation in fragment answer, double negation and constituent negation. In a sequence such as (151) -What did you work for? -For nothing in the end.

there is no other potential source of the negative reading than the n-word with constituent scope in the fragment answer. Such uses are out for PSI with an indefinite value.

But so what? Why does it matter whether an item has a negative value or whether it inherits it from some clausal operator, overt or covert, that could simply be stipulated even when it is not plausibly there? Well, it matters because it has an impact on the analysis of the negation system. Think of the typologist looking at an exotic language. Is an item that is routinely occurring after the main clausal negative marker an indefinite licensed by it, or a negative concording with it? The answer will tell us whether we are looking at a language with negative items, and whether these items enter concord relations. And it has an impact on the theoretical appreciation of a language, and of languages. For Hedde Zeijlstra, n-words have an (uninterpretable) negative feature, which must be licensed by a clause-mate item/operator with an interpretable negative feature. However, no discernable operator can be observed in some of the cases that we have analyzed, notably in constituent negation. Hence the idea that the negative value is introduced by the n-word itself. One consequence is that the negative value of the n-word is independent from its participation in concord relations. An n-word is a negative, and it may or may not concord, as illustrated in examples (1)-( 9) above.

The criterial environments of negative value are shown to organize in a pathway of variation and change, as demonstrated by looking at Finnish, French, American English and Italian data. The first micro-step is fragment negative answers. Fragment negative answers can be expressed by items with a majority use in the bridging context of strong negation (under the command of clausal negation or without). This is demonstrated by the history of the French strong NPI du tout 'at all' and possibly by the contemporary uses of PSIs in vernacular Finnish. The second step is double negation and constituent negation. These can be communicated by full-blown n-words, as shown by rude PSIs, and are inaccessible to mere NPIs, as shown by French du tout and Finnish PSIs. These therefore constitute switch contexts in the sense of grammaticalization: items that display these uses must be analyzed as n-words by learners. What is not clear is whether there is an implicational order between double negation and constituent negation. While rude PSIs in Italian and American English can express constituent negation, there is variance as to whether they enter double negation. Clearly, while significant work has been accomplished here, more is required to define the exact shape of the pathway into negativity.

( 20 )

 20 Nobody said anything (21) * Anybody said nothing. Thus, n-words can indeed license NPIs. They also engage in focus effects: (22) Nobody wrote daily to Margot. (= They wrote all right, but not daily) (23) Nobody knows everything. (= Everybody knows something, but not everything)

( 31 )

 31 He didn't find work at all. (a.) (32) Nobody found work at all. (a.) (33) Did she find work at all? (b.) (34) If somebody found work at all, it must be her. (c.) (35) Everyone who found work at all that week was considered employed. (d.) (36) Few people find work at all in Little Horton. (e.) (37) ?? He may find work at all. (f.) (38) ? I hope that he found work at all. (g.) (39) ?* Find work at all. (h.) (40) ?* One finds work at all in Little Horton. (i.) (41) Before she was at all able to find work, she had to change fields. (j.) (42) * He'll find work at all. (k.) (43) * She found work at all yesterday. (l.) Greater restrictions still are displayed by French equivalent du tout. It is not only excluded from FC environments, but also from weak polarity contexts (anything other than the strong contexts in the scope of clausal negation and without), as shown by the elicitations below that are straight translations of the English examples above. (44) Il n'a pas du tout trouvé de travail. (a.) (45) ? Personne n'a du tout trouvé de travail. (a.) (46) ?* A-t-elle du tout trouvé du travail ? (b.) (47) ?* Si quelqu'un a du tout trouvé du travail, ça doit être elle. (c.) (48) * Tous ceux qui ont du tout trouvé de travail cette semaine-là étaient considérés en emploi. (d.) (49) * Peu de gens trouvent du tout du travail à Little Horton. (e.) (50) * Il pourrait du tout trouver du travail. (f.) (51) * J'espère qu'il a du tout trouvé du travail. (g.) (52) * Trouve du tout du travail. (h.) (53) * On trouve du tout du travail à Little Horton. (i.) (54) * Avant d'être du tout capable de trouver du travail, elle a dû changer de domaine. (j.) (55) * Il trouvera du travail du tout. (k.) (56) * Elle a trouvé du travail du tout hier. (l.)

( 63 )

 63 Never has he worked at all. (NC, *DN) (64) Jamais il (n') a travaillé du tout. (NC, *DN) Neither does it give rise to constituent negation uses. (65) * He has worked for *(nothing) at all. (66) * Il a travaillé pour *(rien) du tout.

  14 . Type A uses are widely available, as illustrated by internet examples that all express ignorance: (90) Non ho capito un piffero / un tubo / un cazzo NEG have-PR-1PS understand-PTCP a dick I haven't understood jackshit (91) G Scusa, Ga ma non ho capito un piffero. (92) G Ho una professoressa che spiaga malissimo e non ho capito un tubo delle rette nel piano cartesiano. (93) G sono arrivata quasi a 40 anni e non ho capito un cazzo della vita. Associated to the emphatic speech of youth, Type Z are also attested (though I have not found piffero) (94) Ho capito un piffero / un tubo / un cazzo I have understood jackshit (95) G Ho fatto una piccola ricerca...e ho capito un tubo. (96) G del resto siete sempre stati su marte perché hai capito un cazzo ops scusate politicamente parlando ... In either case, the items occur with an indefinite article. It can occur with a n-word determiner (97) G Non c'è nessun disco. Non ho nessun cazzo di disco.

( 145 )

 145 No professor favors NOTHING. (= favored some) (146) No professor favors SQUAT. (=/= favored some)

  ; for a similar case in Brazilian Portuguese, seeSchwenter,

	Dickinson & Lamberti 2019). Examples are cited by Vilkuna, such as the following
	a. -Huijaa-t
	cheat-2SG
	You're cheating.
	-Mä	mi-tä=ä	huija.
	I	what-PAR=CLT cheat.CNG

I'm not! (Vilkuna 2015 : 481) Alsenoy & van der Auwera note that "there are also examples involving indefinites, e.g., paskat sä mitään tiedä (shit.PL you what.PAR.INDEF know.CNG) 'Shit, you don't know anything

Table 1 .

 1 's table of polarity environments. Negative polarity environments Restrictions are however found in Free-Choice environments (noted FC in the table) and in the future.

	any	shenme Kanénas/	Greek FCI
		rato NPI	otidhipote

  Ce n'est pas vrai qu'il a trouvé du tout du travail. It's not true that he found work at all.

	57) sans	qu'	il ait		du tout	trouvé	du travail
	without	that he have-SUBJ-3PS at all	find-PRTC of work
	without him finding work at all
	(58) Ce n'est pas du tout vrai qu'il a trouvé de travail.
	It's not true at all that he found work.
	(59) *Sans	qu'	il		soit	vrai
	without	that 3PS-NOM	be-SUBJ-3PS true 3PS found work.
	qu'il ait			trouvé	du tout	du travail.
	that he have-SUBJ-at all	find-PRTC at all	of work
	without it being true that he found work at all
	(60) *

Table 2 .

 2 Historical evolution of readings of French at all, in numbers

			Ambiguous	High	Weak	Strong	Irrelevant	Totals
			between	degree	negative	negative	cases
			literary		polarity	polarity
			and high
			degree
	1550-	4	2	75	1	16	2	100
	1600-	3	2	73	2	20	0	100
	1625-	1	1	53	2	37	5	100
	1650-	4	1	2	0	74	19	100
	1700-	16	1	0	0	83	0	100
	1750-	14	0	0	1	85	0	100
	1800-50 9	0	0	0	91	0	100
		51	7	203	6	407	26	700

  An analysis is proposed by Postal (see also2014, 2017). In his terminology, "Type A", illustrated by the didn't say dick case, behaves like a straight NPI, in being under the command of a clausal negative that precedes it. The distribution of "Type Z", illustrated by knows fuck all, appears comparable to that of a n-word. However, the comparability seems rather superficial to Postal. Differences are found with respect to the polarity of tag questions, don't think parentheticals, choice of either rather than too, continuation by not even, concurring negative answers, negative fronting and licensing of NPIs. Olmstead knows (nothing/ * squat), not even the name of the capital of Botswana. (80) Olmstead knows (nothing/ * squat). -No, I guess not. (81) (Nothing/ * squat) does he know about anyone here. (82) Olmstead knows (nothing/ * squat) about anyone.

	74) Olmstead didn't say dick about the new dean. (2004: 159, ex. 2a)
	(75) Olmstead knows fuck all about Botswana. (2004: 159, ex. 2b)
	(76) Olmstead knows (nothing/ * squat) about Botswana, does he?
	(77) Olmstead knows (nothing/ * squat) about Botswana, I don't think.
	(78) Olmstead knows (nothing/ * squat) about Botswana and Rufus knows (nothing/ *
	squat) either.
	(79)

  ) Samantha cares (nothing / * squat / * zero) about Burmese cats, does she? (84) Samantha cares (nothing / * squat / * zero) about Burmese cats, I don't think. (85) Samantha cares (nothing / * squat / * zero) about Burmese cats, and Sandra cares (nothing / * squat / * zero) either. (86) Samantha cares (nothing / * squat / * zero) about Burmese cats, not even champagne ones. (87) Samantha cares (nothing / * squat / * zero) about Burmese cats. -No, I guess not. (88) (Nothing / * squat / * zero) does Samantha care about Burmese cats, I must say. (89) Samantha cares (nothing / * squat / * zero) about any cat, really.

  listed by Postal is quantified in the table below.The attestations call for a few remarks. On the one hand, the investigated forms appear relatively infrequent in a half-a-million word corpus, which is probably due to the taboo nature of (component parts of) the expressions. This makes it all the more remarkable that the collocation with verb to know represents 44 occurrences, nearly one in four. Uses is dominant in object position(Horn 2001b: 327, footnote 31), although not exclusive.

	(112) they've said pretty much jack-squat about what we can expect t
	(113) Regan did sweet piss-all
	(114) Emmett knew shit-all about pens and horses and dirt
	(115) HONORING OUR RUBBER-STAMP CONGRESS, WHOSE MEMBERS HAVE
	FOUND PLENTY OF TIME TO DO SQUAT
	Fragments
	(116) and what do you have to show for it? Zip, nada, fuck-all.
	(117) Yeah, but what are they gon na find? Fuck-all.
	(118) What're you doing to help her, huh? Jackshit, that's what.
	(119) I know shit about video games. Jackshit, even.
	(120) you know what our chances are of winning a Nobel? -Zero. -Squat.
	NPI	N-word	Fragment	Totals
	didley Complement of a noun 1	2	0	3
	fuck-all (121) Jackie snorted. The king of nothing. The king of fuck-all. 7 36 8	51
	jackshit (122) know what your promise is worth to me? Huh? Fifty per cent of fuck-all! 7 7 2 16
	jack-squat (123) X plus fuck-all equals X. 2	1	0	3
	piss-all (124) a world where the facts don't add up to a Grand Unified Theory of jackshit. 1 1 0 2
	shit-all squat Indirect object Totals (125) Poise and concision in debate answers counted for fuck-all, 2 2 0 66 28 6 86 77 16 (126) people as you'd phrase it have to live under constant threat of death with fuck-all 4 100 179 Table 3. Rude PSIs in the COCA corpus, in numbers support from the likes of you?
	(127) earning $10-50,000 pay 15% in income taxes for that healthcare. Ours pay about.... Each category is illustrated in turn. squat.
	Type A uses (128) A divorce decree or settlement doesn't count for squat with a creditor.
	(102) with Virginia and Florida breaking for Obama, Ohio won't matter didley. Adverbial (103) But other than that, we ain't changing' fuck-all. (104) and you cant do jack-shit about it. and neither can the powerless hyperpower. (129) Do nt keer fuck-all about the damn hoss.
	(105) To pretend to know that the President " doesn't know jack-squat about economics " is Determiner horribly pretentious, (130) So you have fuck-all evidence of a campaign for his job despite the smoking gun of (106) You don't know piss-all, really internal emails. (107) I don't know shit-all about them (131) CQC in MGS3-4 made fuck-all sense, (108) What's interesting is no one says squat about Dublin Core (132) What about burgers? There's fuck-all meat in them
	Type Z Subject (109) Obama change did didley squat. (133) and the fuck-all they know about Libertarian ideals gets spoon-fed to them by the likes (110) You reap what you sow, darling, and you've sown fuck-all. of Randi Rhodes (111) Fucking demorats have done jackshit in speaking out against Syria, Iran, Libya or any (134) and the vocal is, yet again, puking out demonical and bipolar emotion like fuck-all other Obama nation. matters.
	(135) No wonder fuck-all Americans got a passport.
	(136) But fuck-all has worked the way I wanted.

  The following shows that nothing finds parallelism to fuck-all (139) Olmstead knows (nothing / fuck-all / * squat) about Botswana, does he? (139) Olmstead knows (nothing / fuck-all / * squat) about Botswana, I don't think. (140) Olmstead knows (nothing / fuck-all / * squat) and Rufus knows (nothing / fuck-all / * squat) either. (141) Olmstead knows (nothing / fuck-all / * squat), not even the capital of Montenegro. (142) Olmstead knows (nothing / fuck-all / * squat). -No, I guess not. (143) (Nothing / Fuck-all / * squat) does he know about anyone here. (144) Olmstead knows (nothing / fuck-all / * squat) about anyone.

"N-word" standardly refers to items other than the clausal negatives that can communicate a negative value in a fragment answer. The new term "Negative Concord Item" has been coined by some to avoid confusion with the homonymous racist expression. However, the former applies to the French and Italian items, and not to the English ones, that in the standard variety do not enter concord relations. Another term must then be used for the English n-word type, usually "negative quantifier" (see Zeijlstra

2020) (although confusingly "negative quantifier" is sometimes used for the French and Italian n-word type as well, e.g.[START_REF] Willis | Negative polarity and the Quantifier Cycle: Comparative diachronic perspectives from European languages[END_REF]. As this distinction appears undesirable to us for the very reasons presented in this paper, we retain the old expression, which should not be seen as support for racism in any shape or form.2 In this paper, given the extent of the bibliography on the subject, references are largely restricted to those published this century, forerunners being discussed in[START_REF] Giannakidou | The Landscape of Negative Dependencies: Negative Concord and N-Words[END_REF],[START_REF] Giannakidou | Negative concord and the nature of negative concord items[END_REF][START_REF] Giannakidou | Negative[END_REF] andHorn (2001a), among many others.

"Negative Polarity Items" refers to indefinites whose distribution or interpretation is tied to contexts such a negation, question and conditionals.

Other contexts have been adduced, particularly modification by almost, but such modification is not conclusive, because its ungrammaticality depends not on NPI status of the modified term, but on the incompatibility between almost and clausal negation: consider *I didn't see almost anyone vs. (?) Without seeing almost anyone.

A reviewer remarks that if Italian preverbal n-words had a different status from the post-verbal ones, only the former would be expected as negative fragment answer, which is not the case: Nessuno is equally acceptable as an answer of either Chi ti ha visto?'Who saw you?' or Chi hai visto? 'Who did you see?'.

There is considerable confusion about the use of the term "constituent negation". It may be used to refer to a negation with clausal scope that syntactically attaches to a specific constituent (see den Dikken 2019, Garzonio 2016). a. He wrote not two but three letters of complaints to Tesco. (see Déprez 2018) b. Not everybody is up for parachute jumping. (see Etxepare & Uribe-Etxebarria 2016)c. Not speaking a foreign language is a disadvantage.(Iordachioaia 2009: 199) However, it is not clear that the negative in these sequences does not scope over a predicate. It is specifically the local scope, that does not affect a predicate, as in (19), that we designate here with the expression "constituent negation".

Put forward by[START_REF] Giannakidou | Polarity sensitivity as (non)veridical dependency[END_REF], the term "Polarity Sensitive Items" is used as a hyperonym of both NPIs and n-words, when the particular status remains to be determined.

That belong to the swearword category (interjective uses of nominals referring to a situation: Ah shit!) , rather than to the insult group (uses of nominals relating to a referent: What a dick(head)!), although as we will see below, Italian draws on the latter.

It is that variety that judgements in this section reflect, and no attempt will be made here to cover other varieties of English.

Whether these are actually minimizers is a question raised by[START_REF] Floricic | Un cazzo, un cavolo, un cacchio, un corno, un tubo, ecc. come termini din polarità negativa ? MS[END_REF]. In view of the difficulty of using even (?* They know not even jackshit about the central bank, vs. They know not even the least bit about the central bank), doubts are permitted. This point I leave to future research.

A similar phenomenon pointed out by a reviewer is I could care less as an equivalent of I couldn't care less. However, the equivalence seems restricted to this sequence, which of course is a clause rather than a lexical expression.

Where the term in the table include their derivatives. Despite its polysemy, squat was looked at to provide a comparative basis; the examination was conducted on the first 500 occurrences out of the 2000+ of singular noun 'squat'.

A case similar to cazzo is French que dalle 'nothing', which while not being rude (the literal meaning is not transparent), is of lower registers, and has a similar ability to expression preverbal negation without concord (Que dalle il a fait, lit. 'Nothing at all he did'), to be used as a negative fragment answer, as constituent negation, with a similar disparity among speakers regarding the double negation reading (? J'ai PAS fait que dalle, lit. 'I did NOT do nothing'). Thus, the evolution path of cazzo is not exceptional.

Acknowledgement

I am grateful to Paul Postal and David Willis for discussions; to Rea Peltola and her contacts for information about Finnish; to Silvia Ballaré, Franck Floricic, Chiara Gianollo, Alda Mari and Cecilia Poletto for their input on the Italian data.


Leïla Chassery

Gaëtan Texier

Vincent Pommier De Santi

Hervé Chaudet

Nathalie Bonnardel

Liliane Pellegrin
email: liliane.pellegrin_chaudet@univ-amu.fr

Vincent Pommier

De Santi

A COVID-19 outbreak on board ship: Analysis of the sociotechnical system of epidemiological management in the French Navy

Keywords: Outbreak management, COVID-19, complex socio-technical system, incident analysis, AcciMap, risk management framework

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

In December 2019, several cases of pneumonia were recorded in the Chinese city of Wuhan, caused by a then unknown virus. On 7 January 2020, after alerting the World Health Organization (WHO), the Chinese authorities confirmed the emergence of a new disease, which was officially named COVID-19 by the WHO on 11 February. The latter was caused by a virus belonging to the coronavirus family, referred to as SARS-CoV-2 to differentiate it from the SARS-CoV virus that was responsible for the SARS epidemic in [2002][2003]. The epidemic gradually spread beyond China and affected a growing number of countries, taking advantage of international travel. It eventually paralyzed almost 200 countries, thereby threatening the global economy. On 11 March 2020, the WHO officially declared COVID-19 to be a pandemic. France had already had several confirmed cases by 30 January. The virus soon spread rapidly throughout the country, which had officially recorded 145,555 cases, including 28,530 deaths, by 27 May 2020. The scale of the health crisis prompted the government to implement drastic measures and mobilized the entire hospital system.

The French Ministry of Armed Forces joined the Ministry of Health in the fight against COVID-19. The Armed Forces Health Service (SSA) applied the strategy defined by the Ministry of Health to combat, limit and curb the transmission of the virus in all branches of the armed forces. To ensure that the latter could continue their missions, additional measures were adopted to accelerate the epidemiological investigations carried out among the military and civilian personnel affected by the disease. This activity was mainly undertaken by the Center for Epidemiology and Public Health of the Armed Forces (CESPA), which is affiliated to the SSA. CESPA's main purpose is to participate in the epidemiological surveillance of French military forces, whether they are stationed in mainland France or abroad. Its objective is to identify the occurrence of an epidemic in order to manage it and implement public health actions designed to bring it under control it as quickly and as far as possible. Given the spread of the virus within both civilian and military populations, the CESPA team soon had to concentrate all their energy on managing the COVID-19 epidemic. On 7 April 2020, the Ministry of Armed Forces was informed of a COVID-19 outbreak within the French Carrier Strike Group (GAN), then on operational deployment. CESPA was ordered to participate in the management of the situation and to conduct an epidemiological investigation. This outbreak, detected following a stopover in Brest, mainly affected the Charles de Gaulle nuclear aircraft carrier (PAN CDG), where there were more than 1000 confirmed cases. Faced with an outbreak on such a scale, the authorities had no choice but to curtail the deployment and organize the GAN's immediate return. Although no deaths were reported, this outbreak had serious financial and operational consequences for the French Navy.

It therefore seems important to investigate the possible malfunctions or failures that led to this outbreak. We examined the sequence of events leading up to the outbreak on board the aircraft carrier, in order to determine the human and organizational factors involved, with a view to improving them. Social science research on disasters and accidents has emphasized the importance of considering the fundamentally systemic dimension of their causes [START_REF] Bergeron | Covid-19: Une Crise Organisationnelle[END_REF]. Our analysis was therefore based on a review of the data collected during the investigation and attempted to identify the conditions, decisions and actions across the whole epidemiological management system that contributed to the emergence of this outbreak. To this end, we adopted the AcciMap analysis method, which is "used to represent graphically the causal factors involved in a particular accident or safety-compromising incident, occurring within complex socio-technical systems" [START_REF] Waterson | Methodological Considerations in Using AcciMaps and the rRsk Management Framework to Analyse Large-Scale Systemic Failures[END_REF] 2). We chose this approach because instead of focusing on finding out who was responsible, it examines the causal flow of events within the structures that make up the system in order to identify all the conditions and actions that contributed to a given incident.

Theoretical Background

Epidemiological management consists in continuously collecting, analyzing and interpreting sets of medical data in order to detect potential epidemics and, if necessary, trigger the immediate implementation of control measures. This sociotechnical organization relies on a group of medical experts from various complementary fields who are trained in the management of epidemic risk situations. These complex and dynamic situations have many different components that can influence each other but also change independently.

Epidemiological management is therefore carried out in a context of uncertainty about the facts and possible developments, where changes can rapidly take place in space and time, and many organizational and technical constraints need to be taken into account. In a routine context, experts can rely on a set of procedures that allow them to manage epidemic alerts quickly and efficiently, but these procedures are not always sufficient when it comes to resolving certain acute or unexpected situations. Epidemic alerts can have differing degrees of complexity and criticality, and even lead to crisis situations. A crisis can be defined as a generally unexpected event, the consequences of which develop rapidly. It is associated with substantial risks, and can rapidly overwhelm existing resources (i.e., procedures, actions, and personnel) [START_REF] Rogalski | La gestion des crises[END_REF]. Pressures mount, undermining the entire sociotechnical system and hampering the management of the crisis, with operators losing control. The conditions are then ripe for an incident to emerge.

According to [START_REF] Underwood | Systems thinking, the Swiss Cheese Model and accident analysis: A comparative systemic analysis of the Grayrigg train derailment using the ATSB, AcciMap and STAMP models[END_REF], incidents arise from unexpected and uncontrolled interactions between the different levels of a sociotechnical system. Analysis of the sequence of events leading to an epidemic does indeed reveal a complex interaction between the levels of such systems, which may include the work environment, staff, management, business, regulators, and government [START_REF] Pennington | The Public Inquiry into the September 2005 Outbreak of E. coli O157 in South Wales[END_REF]. The dynamic and complex nature of these systems is such that incidents are liable to develop even in the normal course of operations [START_REF] Nayak | When Food Kills': A socio-technical systems analysis of the UK Pennington 1996 and 2005 E. coli O157 Outbreak reports[END_REF]. When critical events occur, systems allocate their resources to coordination and adaptation, which reduces their management capacity and increases the risk of incidents. Epidemiological management is a command and control system based on a fixed and linear structure that may rapidly start to show cracks in a crisis situation. For [START_REF] Celik | From linearity to complexity: Emergent characteristics of the 2006 avian influenza response system in Turkey[END_REF], a system that relies on fixed procedures may find it hard to adapt to a new situation by reorganizing staff and resources. External crisis-related influences (e.g., political, financial and media factors) are a source of instability at every level. Maintaining control is therefore a process that involves the entire sociotechnical system [START_REF] Svedung | Graphic representation of accident scenarios: Mapping system structure and the causation of accidents[END_REF].

Figure 1. The sociotechnical system involved in risk management [START_REF] Svedung | Graphic representation of accident scenarios: Mapping system structure and the causation of accidents[END_REF] Rasmussen (1997) considered that every level of the system should be involved in safety management, by controlling the processes that are carried out through laws, regulations and instructions. Through their various decisions and actions, all actors and organizations can shape "a causal path through the landscape along which an accidental course of events sooner or later may be released" (Rasmussen and Svegun, 2000, p. 17). Rasmussen broke sociotechnical systems down into their technical, human and organizational dimensions, and modeled them (See Fig. 1) as different strata ranging from legislators to organizations and their functioning [START_REF] Di Cioccio | Articuler Sécurité et Performance: Les Décisions d'Arbitrage dans le Risque en Aéronautique[END_REF]. For systems to operate safely, decisions made at higher levels must be promulgated and reflected in decisions and actions occurring at lower levels.

By the same token, information must move from lower levels up the hierarchy to inform the actors who make decisions at higher levels [START_REF] Waterson | Remixing Rasmussen': The evolution of AcciMaps within systemic accident analysis[END_REF]. As in risk management, the occurrence of an incident involves ever single level. It is therefore important to conduct an overall analysis of that incident. Systems should be studied as whole entities rather than being considered in their separate parts. To this end, [START_REF] Rasmussen | Risk management in a dynamic society: A modelling problem[END_REF] laid the foundations for a systemic approach that aims to represent the complex interaction between the decisions and actions leading to an incident: the AcciMap method. This method makes it possible to identify, and represent in graphic form, the causal factors and the events that led to an incident at all the levels of the system that were impacted. Unlike analysis methodologies intended to apportion responsibility, this model seeks to produce a more global representation than the traditional causal tree, based on information about the parameters contributing to the incident and the conditions under which it took place [START_REF] Lim | Organisational Aspects into the Return on Experience-The Major Accident[END_REF]. "As is the case with the causal tree normally used to represent the findings from post-hoc accident analysis, the basic AcciMap is developed from analysis of one particular accident case" (Rasmussen and Svegun, 2000, p. 20). Nevertheless, this approach focuses not only on the direct sequence of events and actions leading to the incident, but also on the preconditions that may have influenced or conditioned its occurrence. It therefore also aims to identify the factors for optimizing the operation and safety of the system.

Methodology

Data collection

To obtain a set of precise data on the timecourse of events leading to the COVID outbreak on board the aircraft carrier, we opted for the so-called participant observation method. According to [START_REF] Bogdan | Introduction to Qualitative Research Methods[END_REF], participant observation is a process of field study, characterized by a period of sustained social interaction between researchers and participants. During this period, observers totally immerse themselves in the lives of their targets, in order to share their experiences, carry out exhaustive data collection, and grasp all the subtleties [START_REF] Soulé | Observation participante ou participation observante? Usages et justifications de la notion de participation observante en sciences sociales[END_REF]. As in-house CESPA researchers, we had the opportunity to come into direct contact with some of the actors, and gain access to information that is usually difficult to obtain. This involved taking advantage of our role to observe the situation from the inside. To this end, the purpose of our study was made public to CESPA staff from the very outset. As participating observers [START_REF] Gold | Roles in sociological field observations[END_REF], we gained access to a great diversity of information, whilst respecting the confidential and ethical nature of ergonomic psychology.

We were thus able to compile a timeline retracing the intervention by CESPA operators. This involved noting down all the observations made by the CESPA teams in charge of investigating the epidemic. Participating in the activity of the operators also allowed us to retrieve the documentation we needed to gain a precise understanding of the situation. Our analysis was mainly conducted on a set of public documents, such as the written transcript of a speech made by the Armed Forces Minister on 17 April 2020, the general public summary of the investigations relating to the COVID-19 outbreak on the aircraft carrier, and the report of the epidemiological investigation carried out by CESPA. Other internal documents (e.g., logbook, minutes of meetings, daily situation reports) were used to guide our understanding and clarify the chronology of events. These were studied with scrupulous respect for professional secrecy.

The AcciMap Method

To take into account the whole sociotechnical context in which the outbreak occurred on board the aircraft carrier, we chose to analyze the data we collected using the AcciMap method. Developed by Rasmussen in 1997, then Svedung and[START_REF] Rasmussen | Proactive Risk Management in a Dynamic Society[END_REF]2002, this method makes it possible to build a graphic representation of the different causes of the incident at every level, showing their distance from the result [START_REF] Branford | Guidelines for AcciMap analysis[END_REF].

Providing both a horizontal description of the sequence of events and a vertical description of the factors that had impacted the course of the incident [START_REF] Morel | Sécurité et résilience dans les activités peu sures: Exemple de la pêche maritime[END_REF], its purpose is to highlight the events, decisions, and actions that caused the sociotechnical system to lose control [START_REF] Branford | Guidelines for AcciMap analysis[END_REF], and identify any corrections and improvements that can be made at the different levels of the system, in terms of laws, regulations, instructions and procedures:

1. Government: safety legislation developed to control professional procedures; 2. Regulatory and expert bodies: application of occupational safety legislation; 3. Local government: company policy and administrative application of regulations; 4. Technical and operational management: specification and supervision of staff activities with reference to company rules and policies; 5. Physical processes and human activities: operators responsible for following their managers' instructions; 6. Equipment and surroundings: premises and materials made available to operators to carry out their activities in compliance with company rules.

The bottom level (Level 6) corresponds to the contextual elements, physical characteristics and topography of the places configuring the environment of the incident, Level 5 to the events and causal relationships directly involved in the unfolding of the incident, and Levels 4, 3, 2, and 1 to all the human actors whose decisions influenced the conditions leading to the incident.

Rasmussen also designed a more general modeling framework, the ActorMap model, which provides an overview of the various components of the system under scrutiny, as well as the interactions between them. This type of graph is intended to allow a better understanding of the flow of interactions between the different decision-making bodies that can lead to incidents. Although Rasmussen's approach was originally developed to analyze industrial accidents, it can be reconfigured and adapted (following the author's recommendations) to extend its use. This flexibility allows the approach to be applied to other disciplines, such as medicine and epidemiology. Several epidemics have already been studied using the AcciMap method, including the Clostridium difficile outbreaks in the Maidstone and Tunbridge Wells NHS Trust in England [START_REF] Waterson | A systems ergonomics analysis of the Maidstone and Tunbridge Wells infection outbreaks[END_REF], and the Escherichia coli O157:H7 outbreaks in Scotland in 1996 and Wales in 2005 [START_REF] Nayak | When Food Kills': A socio-technical systems analysis of the UK Pennington 1996 and 2005 E. coli O157 Outbreak reports[END_REF].

Analysis

Our AcciMap model was designed according to [START_REF] Rasmussen | Proactive Risk Management in a Dynamic Society[END_REF]'s guidelines. These authors proposed using a graphical code to clarify the representation (see Fig. 2). The influencing factors (decisions, actions, events) are modeled as interconnected rectangles. However, unlike usual causal representations, an AcciMap diagram not only includes the events and actions that were directly related to the occurrence of an incident, but also represents all the players in the sociotechnical system whose decisions influenced the conditions leading to the incident [START_REF] Svedung | Graphic representation of accident scenarios: Mapping system structure and the causation of accidents[END_REF]. The links shown in the model therefore represent influences without necessarily implying a causal relationship.

Factors that are directly linked are modeled as contiguous rectangles. The graph also features preconditions and priorities that are useful for understanding and contextualizing the unfolding of events. These items, which were not subject to analysis, are represented by rounded rectangles, to distinguish them from other factors. We chose to add a timeline below the diagram to give a more precise indication of the timing of the facts. An approach to structure an "AcciMap" and a proposed legend of standardize symbols [START_REF] Rasmussen | Proactive Risk Management in a Dynamic Society[END_REF] To conduct our analysis using the AcciMap method, we first focused on the aircraft carrier's epidemiological management system. Examining the usual functioning of the system allowed us to identify the decisions and interactions that took place within and among its components. This preliminary research led us to produce an ActorMap representing the different actors and entities that made up the system, as well as the communication flows between them. All the documents and reports we had retrieved were then studied in detail.

The information we extracted was analyzed in order to reconstruct the sequence of events that led to the COVID-19 outbreak on board the aircraft carrier (see Table 2). The AcciMap model was then constructed, following the steps set out in Table 1, and validated by the CESPA experts who had been most closely involved in the management and subsequent investigation of the epidemic.

Step Details 1 Identification of the starting point for analyzing the outbreak.

2 Identification of the human actors at each level of the system who were involved in the occurrence and management of the incident (see Table 2 and Fig. 3).

3 Identification of the external factors and decisions involved in the incident.

4

Identification of the intermediate consequences and final outcome.

5

Arrangement of the elements we had identified according to their level and timing.

6 Insertion of links between these elements.

7 Addition of a timeline indicating the chronology of the events.

Table 1. Steps followed to construct the AcciMap.

Results

Usual outbreak surveillance and management process on the aircraft carrier

We began our analysis by identifying the entities and human actors that made up the aircraft carrier's epidemiological management system. After describing the functions performed by the various actors, we identified their level within the system and the connections between them. The apex of the systemic structure is divided into two parts: civilian and military. On the civilian side, the Ministry of Solidarity and Health is responsible for implementing government policy in the areas of social affairs, public health, and social protection. To carry out its public health missions, the Ministry relies on the Directorate of Health (Level 1), which draws up public health policy and contributes to its implementation, and on centers of expertise (Level 2), such as the National Health Agency, which specializes in epidemiological surveillance. On the military side, health management is the responsibility of the SSA, which is answerable to the Ministry of Armed Forces (Level 1). The SSA guarantees medical and surgical support for the French armed forces, both in metropolitan

France and in overseas theaters of operation. As such, it contributes to public health policy, in collaboration with the Directorate of Health, through CESPA (Level 2). The latter is in charge of the epidemiological surveillance of the entire French military population, and helps to implement and disseminate the SSA's recommendations to the forces' various medical services. As such, it is the first point of contact for the army's services and medical managers (Levels 3 and 4) if there is an epidemic risk or actual outbreak.

Level 3 of the epidemiological management system includes the Chieftaincy of the Health Service for the Naval Task Force, which is responsible for the preparation, support and technical control of on-board medical services. It is under the technical authority of the SSA and the functional authority of the squadron vice-admiral of the Naval Action Force (Level 3).

Level 4 is occupied by the chief medical officer (answerable to the Chieftaincy of the Health Service) and the commander of the aircraft carrier (answerable to the squadron vice-admiral).

The chief medical officer is responsible for the medical team on board the aircraft carrier, which generally consists of three doctors, eight nurses and a medical secretary. It can be reinforced by surgical staff on request. The commander has administrative responsibilities for carrier personnel, equipment and finances. Together, the chief medical officer and the commander are responsible for taking medical decisions regarding the crew, with input from their respective chains of command. The carrier's medical team and crew are located at Level 5.

Thus, the first three levels of the system concern government agencies and centers of health expertise, overseeing civilian and military epidemiological management. The next two levels correspond to the different hierarchical and functional strata within the aircraft carrier.

We therefore observe a geographical separation between the supervisory levels (metropolitan France) and the other levels of the system (on board the ship). Despite this separation, we noted a need for the exchange of information between the two. The assessment of communication links also revealed the involvement of civilian bodies with oversight of the military's decision-making strategies concerning the epidemiological surveillance of COVID-19 within the armed forces. This first phase of analysis allowed us to produce an ActorMap

showing the communication links between the components of the system under scrutiny (see Fig. 3). announced on 14 March, prompted the commander of the aircraft carrier to put in place strict measures on leaving Brest. Over the following 2 weeks, as the aircraft carrier continued its mission in the North Sea, a steady stream of sailors (approx. 12) arrived in the ship's hospital with respiratory symptoms. These patients were not identified as possible cases of COVID-19 by the medical personnel, who instead attributed their symptoms to their working conditions, as some of them were working on the flight deck in strong winds and temperatures approaching 0 °C. On 30 March, during a stopover in Denmark, a dozen sailors went ashore.

The same day, the commander, with the go-ahead of the medical service, which still believed that the disease was not present on board, decided to relax the health measures and agreed to allow a concert by the carrier's amateur orchestra to be held in the ship's aircraft hangar.

The first signals of the disease came on 5 April, with an increase in the number of consultations and hospitalizations for respiratory symptoms. Possible cases were processed in the ship's infirmary and then placed in isolation in the forward sections of the ship. On the same day, one of the sailors who had gone ashore in Denmark sent word to the aircraft carrier that he had tested positive. The commander was then made aware of the presence of the virus within the aircraft carrier. He ordered the resumption of restrictive health measures, but decided to continue the carrier's mission off the northern end of the Bay of Biscay. Despite the health measures, the epidemic continued to grow, with more than 30 sailors showing symptoms of the disease. On 7 April, faced with an increase in the number of possible cases, the commander decided to alert the military authorities and the Ministry of Armed Forces.

The Minister immediately halted the mission and ordered the aircraft carrier to return to Toulon, so that the crew could receive appropriate medical care. A team of epidemiologists arrived on board the aircraft carrier on 8 April. Samples were taken, biologically confirmed the presence of the virus in 50 sick sailors. The initial assumption was that the virus had arrived on board during the stopover in Brest. COVID spread so rapidly that it overwhelmed the ship's logistical organization, with its hospital and isolation facilities full to capacity. On their arrival in Toulon on 13 April, after biological tests, all members of the ship who were diagnosed as having COVID-19, were placed in quarantine on shore. By the end of the epidemic, a total of 1,148 seafarers had been classified as confirmed cases. Although no deaths were reported, two sailors had a severe pulmonary form requiring intensive care treatment. Once the situation had stabilized, the Ministry of Armed Forces ordered the armed forces inspectorate, the naval inspectorate and the SSA inspectorate to carry out investigations in order to understand and learn from this event. CESPA was officially appointed on 19 April to conduct the epidemiological investigation.

AcciMap analysis results

The AcciMap model based on the final analysis is shown in Figures 4, 5 and6. Although entities at the third level of the epidemiological management system may have been involved

in the course of the outbreak, they are not explicitly mentioned in the documents we used in our study. For this reason, although Level 3 was present in the the ActorMap, it does not appear in our AcciMap model. The announcement of the transition to Stage 2 of the epidemic in France served as the starting point for our analysis of the events that led to the outbreak, as it led to the publication of a series of recommendations on which the SSA exclusively relied to enact its epidemiological surveillance strategies. These included case definition criteria, diagnostic methods (biological analyses), and criteria for accessing these analyses, restricting their use to persons identified as possible cases. The carrier's commander and medical team relied on these guidelines to develop their course of action. This resulted in health checks of all personnel on board and, if necessary, medical monitoring to detect the emergence of evocative symptoms based on the definitions that had been communicated to them. In the absence of biological diagnostic testing facilities on board, the medical team had to rely on the possible case definition to diagnose the presence of COVID-19 cases in the crew.

However, the clinical criteria taken into consideration and included in the definition were not enough for the on-board medical team to detect the presence of the disease among crew members. Health and safety measures within the ship had been strengthened as the situation in metropolitan France changed, and procedures had been updated. In particular, during the stopover in Brest, no on-board visits had been allowed, seamen who went ashore were forbidden to go to the clusters that had been identified at that time, and all personnel joining the ship had to complete an exposure risk assessment questionnaire. The transition to Stage 3 of the epidemic on French territory during this stopover led the commander to establish rigorous distancing measures, with no gatherings, less frequent briefings, new rules for playing sports, and restrictions on the number of people in collective settings. In the 14 days following the stopover, the health authorities announced the discovery of two new characteristic clinical criteria: anosmia and ageusia. However, although armed forces physicians were informed of these criteria on 27 March, the latter were not included in the possible case definition, and do not seem to have come to the attention of the on-board medical team. Medical personnel therefore continued to use the clinical criteria for acute respiratory syndromes and fever, set out in the possible case definition, to detect the virus.

However, the primary function of these criteria was to standardize epidemiological reporting, and they were not enough to allow a diagnosis of the disease. Although there was a moderate but constant flow of sailors to the infirmary presenting with respiratory symptoms, the medical team, focusing on the instructions given by the authorities and convinced of their diagnosis, failed to detect the signals of virus spread among the crew. Believing that the disease was not present on board the ship, and aware of the impact of the restrictive health measures on crew morale, the commander decided to relax these measures from 30 March. A concert was held that same day in the aircraft hangar, bringing together 532 sailors, some of whom were subsequently identified by epidemiological investigators as carrying the virus on that date. The spread of the disease then accelerated until 5 April, when the increased flow of patients admitted to the infirmary for respiratory infections began to raise suspicions. It was only when one of the sailors who had disembarked in Denmark reported that he had tested positive that there was a real awareness that there might be an established COVID-19 outbreak on board. The commander ordered the immediate resumption of strict health and safety measures, together with the isolation of all possible cases. However, he only inform his superiors 2 days later, thus delaying intervention by the authorities. Despite the arrival of reinforcements from the SSA, the scale of the outbreak was such that the ship' logistical organization was rapidly overwhelmed, with insufficient technical, operational and material resources. The authorities then decided to curtail the aircraft carrier's mission. The AcciMap diagram and the analysis of the decisions and influencing factors that led to the outbreak (see Table 3) show that the epidemic on board the aircraft carrier cannot be attributed to individual decisions, but resulted from an accumulation of multiple factors that interacted at different levels of the sociotechnical system. Although the model focused on two main factors, located at Level 4, analysis revealed the impact of other precursor factors across Levels 2-5 of the system. Analysis also revealed a communication failure between Level 2 and Levels 4 and 5. Better exchanges between the SSA's expert bodies and the medical service on board the aircraft carrier would have doubtless led to earlier detection of the virus among the crew. Likewise, more rapid reporting by the ship's commander would have enabled the authorities to intervene slightly earlier.

Factor Explanation

1 Following the transition to Stage 2 of the epidemic, a series of recommendations is drawn up, providing case definitions for COVID-19 and setting out the diagnostic and epidemiological reporting criteria for the civilian population.

2

The SSA relies exclusively on these recommendations for the implementation of military epidemiological surveillance strategies.

3

In the absence of molecular biological testing equipment on board the aircraft carrier, the medical service relies exclusively on the criteria for case definition communicated to it to diagnose possible cases of COVID-19. It fails to detect the presence of cases on board.

4

The commander decides to continue the aircraft carrier's mission and to maintain the stopover in Brest.

5

The carrier's medical service is not aware of new clinical criteria identified by the Directorate of Health and SSA. They attribute the symptoms presented by some sailors to other causes.

6

Faced with low crew morale and led to believe that the disease is not present on board, the commander decides to relax the health and safety measures and allows a concert to take place on board the aircraft carrier.

7

The carrier commander waits 2 days before informing the authorities of the presence of the disease on board.

Table 3. Influencing factors and key decisions in descending order of importance.

Discussion

Aircraft carriers are aeronautical platforms with continuous personnel movements, both between ships and with land. There were therefore numerous opportunities for contamination from the very start of the mission. The epidemiological investigation carried out by CESPA traced the dynamics of the epidemic and concluded that the virus had first arrived on the ship as early as late February. Although the origin of the contamination could not be precisely determined, the first cases were confirmed a posteriori, based on the presence of anosmia and ageusia, which are now recognized as more disease-specific symptoms. The epidemiological investigation therefore showed that the Brest stopover should not be regarded as triggering the epidemic on board. Nevertheless, it may have allowed the virus to be reintroduced, and with the subsequent easing of measures on 30 March, the disease quickly spread among the crew.

The investigation highlighted two days of high spread, on 31 March and 1 April, immediately after the relaxation of health and safety measures.

The systemic analysis of the outbreak showed that the diagnostic difficulties encountered by the on-board medical team had an impact on the commander's decision to relax the restrictive measures. The late detection of the epidemiological signal can therefore be regarded as an indirect cause of the spread of the epidemic within the crew. However, the investigation revealed that in the absence of recommendations on how to use the diagnostic tools available on board, the medical service had to rely solely on the criteria defined by Public Health

France, and communicated by the SSA to detect possible cases. These clinical criteria were acute respiratory infection and fever, to which was added a notion of exposure to a risk zone, or contact with a possible or confirmed case. However, the investigation highlighted the very low sensitivity and specificity of these criteria for the detection of the disease within the crew, as the latter were mainly young and did not develop severe clinical forms. The first definitions used to detect cases were based on information provided in the scientific literature, and more disease-specific symptoms like anosmia and ageusia were only brought to the attention of French clinicians at quite a late stage. Moreover, although these additional detection criteria were made public by the Directorate of Health on 22 March, this news does not appear to have reached the medical service of the aircraft carrier. The epidemiological investigation clearly showed that the use of these two clinical criteria for screening possible cases would undoubtedly have made it possible to detect the epidemiological signal as early as 23 March.

There was clearly a dysfunction in the dissemination of information and recommendations, leading to gaps in benchmarks for decision-making.

The investigations carried out by the inspectorates of the French Navy and Armed Forces highlighted the factors that led to the aircraft carrier losing control of the epidemic. The carrier's commander, who was utterly confident in his health analysis and epidemiological management capacity, preferred to deal with the situation internally before informing the authorities of the suspected outbreak on board the ship. It was only when the health situation reached epidemic proportions that the commander decided to alert his superiors. The operational and technical organization of the aircraft carrier was soon overwhelmed by the spread of the epidemic, as its hospital capacity was saturated, forcing it to group patients in precarious conditions until their arrival in Toulon. These investigations therefore revealed the limitations of an operation that was too isolated in this context.

Analysis of the outbreak on board the aircraft carrier made it possible to identify problem areas throughout the sociotechnical structure responsible for epidemiological management, and to determine which factors might be improved. The diagnostic difficulties encountered by the medical personnel of the aircraft carrier revealed a need to consolidate the health strategies implemented when a new form of disease emerges, in order to be able to detect early symptoms and conduct a more effective testing campaign. One solution would be to set up a health watch, to monitor all relevant scientific publications, in order to adjust the procedures to be followed at the different levels of medical intervention as quickly as possible. This monitoring would provide military doctors with reliable, up-to-date knowledge, in order to ensure the most appropriate management, according to their medical practice and available resources. In terms of organization and communication, the analysis highlighted shortcomings in the chains of information transmission. Feedback showed the importance of a fluid exchange of information and skills between the different levels of the system, to guarantee rapid and appropriate decision-making. The surveys carried out by the various inspectorates gave rise to a series of recommendations, such as the revision of epidemic crisis management procedures, the establishment of a health surveillance system, the provision of additional equipment and resources to carry out screening, clearer identification of contacts and managers in this type of situation, systematic consultation of experts, and improvements in procedures for exchanging information.

Conclusion

Military epidemiological management has a complex and multilevel sociotechnical structure. In this kind of system, the occurrence of an incident is dependent on a variety of factors, distributed across the structure. Analysis of the outbreak that occurred on board the aircraft carrier showed the involvement of Levels 2, 4 and 5 in the chain of events leading to the outbreak. This led us to identify a series of factors that influenced the decision taken by the ship's commander on 30 March. This relaxation of distancing measures, identified as a key tipping point, is clearly linked to the medical team's failure to detect the virus. The latter seems to have relied solely on the biological criteria that had been communicated to it, without applying any additional strategies that would have allowed it to eliminate all doubt. It turned out that these criteria, defined to guide epidemiological surveillance, were not enough to diagnose the disease. Exchanges with expert bodies would have allowed the team to perform more accurate health assessments. The second key factor highlighted by our analysis also concerns the inadequate transmission of information. Analysis showed that the commander's decision to manage the management internally caused a delay in the intervention of the health authorities. Thus, better communication between the different levels would have made it possible to detect and manage the epidemic more quickly.

Our analysis therefore highlights the importance of good communication between the different levels of the epidemiological management system, for an effective resolution of the situation. As it is, the structural complexity of the system proved to be a source of complication that impeded coordination and cooperation, which are essential in a crisis context. Research in this field has shown that some actors are able "to innovate or to tinker with means of communication or modes of organization for specific circumstances" (Bergeron et al., 2020, p. 102). We believe that this ability is essential for the system to function properly in crisis situations. The findings of social science research show that, in such situations, the procedures and tools available to actors are less important than their ability to work together [START_REF] Bergeron | Covid-19: Une Crise Organisationnelle[END_REF]. The main objective in improving risk management should be to ensure better interaction between the different levels of the system in terms of decision-making and planning strategies [START_REF] Rasmussen | Proactive Risk Management in a Dynamic Society[END_REF]. The uncontrolled and random factors inherent to crisis situations tend to accentuate the mismatch between the planned measures and the reality on the ground, consequently increasing the risk of incidents. In this type of situation, the actors must rely on their knowledge, while being sufficiently imaginative to create new solutions that will overcome the limitations of their procedures and allow the situation to be managed appropriately [START_REF] Pellegrin | Decision-making during nonroutine outbreak management: Toward an exploration of experts' creative decisions[END_REF].

The AcciMap method allowed us to perform a causal analysis that went beyond the identification of shortcomings or human errors. As a result, we were able to study the factors that contributed to this incident at all levels of the epidemiological management system and understand how they combined to generate this event. More specifically, the systemic vision afforded by this approach allowed us to go beyond the most direct causes and detect the higher-level factors that influenced the course of events, or which failed to prevent the outbreak taking place. This type of analysis can be applied to a variety of situations. It is particularly useful for revealing the weaknesses of a given system and for drawing lessons and recommendations for improving safety and preventing similar events in the future.

Nevertheless, feedback mechanisms should not be limited to pointing out errors or malfunctions that need to be corrected, but should also focus on new solutions for addressing the difficulties that are encountered. Future studies should examine the reorganization strategies and new management methods that were implemented by CESPA's epidemiological surveillance team during the first phase of the COVID-19 epidemic.

Figure

  Figure 2. An approach to structure an "AcciMap" and a proposed legend of standardize symbols

Figure 3 .

 3 Figure 3. A Generic ActorMap of the decision-making bodies involved in the occurrence and

Figure 4 .

 4 Figure 4. AcciMap diagram of the COVID-19 outbreak on the aircraft carrier (Part 1).

Figure 5 .

 5 Figure 5. AcciMap diagram of the COVID-19 outbreak on the aircraft carrier (Part 2).

Figure 6 .

 6 Figure 6. AcciMap diagram of the COVID-19 outbreak on the aircraft carrier (Part 3).

Table 2 .

 2 Course of events leading to COVID-19 outbreak on board the aircraft carrier.

	Date	Events

Acknowledgments

We gratefully acknowledge the assistance of Pr. JB. Meynard, Director of the Armed Forces Center for Epidemiology and Public Health, Dr. H. Degui and the entire epidemiological surveillance team: Dr. V. Pommier De Santi, Dr. F. De Laval, Dr. A. Dia, Dr. C. Tong, Dr. F. Letois, Dr. M. Grau, D. Houssin, M. Fossier, C. Brossier, YS. Morin, A. De Bonet d'Oléon, Dr. L. Holterbach, and O. Merle. This article forms part of a thesis carried out within the Research Center on the Psychology of Cognition, Language and Emotion (EA 3273) of Aix-Marseille University and funded by a grant from the Provence-Alpes-Côte d'Azur Regional Council, for which we are particularly grateful.