Margaret E L Renwick
email: mrenwick@uga.edu

Ioana Vasilescu

Camille Dutrey
email: camille.dutrey@lne.fr

Lori Lamel
email: lamel@limsi.fr

Bianca Vieru
email: vieru@vocapia.com

Marginal contrast among Romanian vowels: evidence from ASR and functional load

Keywords: phonology, Romanian vowels, marginal contrast, frequency distribution, functional load, automatic speech recognition, pronunciation variants

, which are considered separate phonemes, although they are historical allophones with few minimal pairs. We consider the vowels' functional load within the Romanian inventory and the usefulness of the contrast for automatic speech recognition (ASR). Using a 7 hour corpus of automatically aligned broadcast speech, the relative frequencies of vowels are compared across phonological contexts. Results indicate a near complementary distribution of [2] and [1]: the contrast scores lowest of all pairwise comparisons on measures of functional load, and shows the highest Kullback-Leibler divergence, suggesting that few lexical distinctions depend on the contrast. Thereafter, forced alignment is performed using an existing ASR system. The system selects among [1], [2], ∅ for lexical /1/, testing for its reduction in continuous speech. The same data is transcribed using the ASR system where [2]/[1] are merged, testing the hypothesis that loss of a marginal contrast has little impact on ASR error rates. Both results are consistent with functional load calculations, indicating that the /2/ -/1/ contrast is lexically and phonetically weak. These results show how automatic transcription tools can help test phonological predictions using continuous speech.

Introduction

A central question in phonological analysis is whether two sounds lie in phonemic contrast with one another, a state traditionally diagnosed by the presence of minimal pairs, in which a single sound change signals a lexical difference. Such a distinction implies that the two sounds must be represented as separate entities in the minds of native speakers, and the set of all contrastive sounds constitute a language's phonemic inventory. Sounds that do not contrast, for example because they lie in complementary distribution, are predictable allophones. Increasingly, however, close analysis of the relationships among sounds has revealed gradient, even marginal, phonological contrasts. Evidence comes from speech production [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF][START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF][START_REF] Nadeu | Variation in the lexical distribution and implementation of phonetically similar phonemes in catalan[END_REF], speech perception [START_REF] Boomershine | The impact of allophony versus contrast on speech perception[END_REF][START_REF] Mora | Effects of spanish use on the production of catalan vowels by early spanish-catalan bilinguals[END_REF] and via sounds' distribution in the language, particularly functional load [START_REF] Hall | A Probabilistic Model of Phonological Relationships from Contrast to Allophony[END_REF][START_REF]A typology of intermediate phonological relationships[END_REF]. Functional load is estimated with measures that consider how languages use particular contrasts, i.e. how many lexical distinctions depend on a single pair of phonemes [START_REF] Surendran | Quantifying the functional load of phonemic oppositions, distinctive features, and suprasegmentals[END_REF][START_REF] Hockett | The quantification of functional load: A linguistic problem[END_REF]. It has been associated with language evolution, that is, the probability that two sounds will merge over time [START_REF] Wedel | High functional load inhibits phonological contrast loss: A corpus study[END_REF], language acquisition [START_REF] Stokes | Ambient frequency, and functional load as predictors of consonant development in children[END_REF], or cross-language comparisons [START_REF] Oh | Cross-language comparison of functional load for vowels, consonants, and tones[END_REF].

In this paper we analyze continuous speech processed by automatic speech transcription tools. Firstly, we investigate the relationship between the frequency distributions of sounds in the corpus and the functional load of contrasts they participate in, acknowledging the effects of contextual conditioning on their distributions. Secondly, we apply forced alignment and ASR experimental methods to gain insight about how crucial a particular contrast is in a given language. We focus on the vocalic inventory of Romanian, a language whose central vowels [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] and [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] are argued to be marginally contrastive on the basis of their distribution in the language; they are historical allophones, and despite the synchronic presence of a few minimal pairs, they are in nearly complementary distribution [START_REF] Renwick | The Phonetics and Phonology of Contrast: The Case of the Romanian Vowel System[END_REF].

Romanian: a brief description

Romanian is a Romance language, mother tongue of about 29 million speakers in Romania and the Republic of Moldova. Although more than 60% of the fundamental vocabulary is Latin, Slavic influence is prevalent in the Romanian lexicon. Today's Romanian is nourished by borrowings from modern Romance languages and English [START_REF] Trandabat | The romanian language in the digital age[END_REF]. The Romanian vocalic system includes seven monophthongs ( [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] and [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF]) that may appear in both stressed and unstressed position, in open or closed syllables, in lexical roots of any length, and in affixes. Vowels may appear adjacent to any consonant, though as we show, certain sequences are more or less likely. Within phonological forms, the root is typically followed by one or more morphological suffixes that place restrictions on the vowels that actually appear in word-final position [START_REF] Chitoran | The phonology of Romanian: a Constraint-Based Approach, ser. Studies in Generative Grammar[END_REF]. Romanian inherited the five vowel qualities of Latin after the loss of length contrast, and developed two additional central vowels [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] and [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF]. [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] arose from Latin [a] in unstressed syllables, and was reinforced by Slavic and other East European idiomatic borrowings. [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] and [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] coexisted in free variation and then in complementary distribution, before becoming separate phonemes in the 16th century, as minimal pairs arose [START_REF] Vasiliu | Fonologia istoricȃ a dialectelor dacoromâne[END_REF][START_REF] Rosetti | Istoria limbii române I: de la origini pînȃ la începutul secolului al XVII-lea[END_REF]. Historically, [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] operated as a stressed, typically pre-nasal allophone of [2] [18]. [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] and [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] are distinct for native speakers, demonstrated by production and perception analyses of laboratory speech [START_REF] Renwick | The Phonetics and Phonology of Contrast: The Case of the Romanian Vowel System[END_REF]. However, recently it has been emphasized that their contrast is severely diminished in continuous speech, leading to a phonetic near-merger [START_REF] Renwick | A phonologically weak contrast can induce phonetic overlap[END_REF].

[a], [e], [i], [o], [u],

Data

The corpus analyzed here consists of broadcast data gathered from various Romanian radio and television shows (7 hours, 141 speakers), from read speech and more spontaneous interactions such as debates. The number of speakers varies according to the source, ranging from 3 to 24 and including both male and female adult speakers. Recordings portray the standard version of the language based on the Southern dialect. Efforts were made to avoid sources with significant quantities of overlapping speech, foreign or regional accents and noisy background. The data were collect and annotated in the context of the Quaero program 1 .

Table 1 sums up the characteristics of the corpus. The data were automatically aligned and segmented into words and phones using the system described in [START_REF] Vasilescu | Exploring pronunciation variants for romanian speech-to-text transcription[END_REF], for which they served as development and evaluation corpora.

Experimental approach

Three experimental approaches are used to gain insight into the phonological patterns of the /2/-/1/ contrast. Frequency distribution of vowels. Comparing the relative frequencies of Romanian vowels can highlight restrictions on the vowels' distributions, as well as their phonological conditioning, in particular of [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] and [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF]. Here, vowel type frequency was calculated across the 9,032 distinct words in the corpus, representing the 56k total lexical tokens. Functional load and contextual frequency. The distributions of /1, 2/ are quantitatively compared using three algorithms available via the Phonological Corpus Tools (PCT) toolkit [START_REF] Hall | Phonological corpustools, version 1[END_REF].

The input to the toolkit is the list of unique words in the corpus, converted to IPA characters, and calculations are run as pairwise comparisons of Romanian vowels, using both type and token frequency measures where available. The weak relationship between [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] and [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] is hypothesized to show in several measures: 1. Functional load is correlated with the presence of minimal pairs; thus it is expected to be low for [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF], [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] with respect to other pairs of sounds. It is calculated on the basis of both type and token frequency in the corpus, using a measure of the change in entropy that occurs when a contrast is neutralized (i.e. merged).

Probability distributions are based on the Kullback-

Leibler divergence score, a calculation of relative entropy. It quantifies the dissimilarity of distributions between two sounds, such that a low score is produced when two sounds appear in the same environments, and a high score is produced when they appear in diverse environments (i.e. when their probability distributions are quite different). Because both [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] and [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] appear preferentially in different contexts, their distributions are expected to diverge. Kullback-Leibler scores are calculated according to (a) the left-hand segmental environment; (b) the right-hand environment; (c) both sides.

3. Mutual information is calculated between a sound and those to its left and right. It is useful in understanding the status of /1/, whose distribution is more restricted than other vowels in the system. We predict an increased relationship of mutual information between /1/ and the contexts where it was conditioned, such as before [m,n,r]; but such relationships are not expected for /2/. Mutual information is calculated using token frequency in the following six ordered-pair bigrams:

{[1, 2]}[n], {[1, 2]}[m], {[1, 2]}[l], {[1, 2]}[r], {[1, 2]}#, #{[1, 2]}.
Forced alignment and automatic speech transcription experiments. Two experiments are run to test the functionality for ASR of the /1/-/2/ contrast:

1. alignment of pronunciation variants for /1/, performed with an ASR system for Romanian [START_REF] Vasilescu | Exploring pronunciation variants for romanian speech-to-text transcription[END_REF]. The speech recognizer selects among [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF], [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] or ∅ (suppression of the vowel) for lexical /1/ on development data (3.5h of the broadcast corpus). The variants are selected to estimate the relation between the effective realization of [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] and [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] and their historical relation through maintenance [START_REF] Renwick | The Phonetics and Phonology of Contrast: The Case of the Romanian Vowel System[END_REF], suppression [START_REF] Avram | [END_REF], or centralization of [1] [19]. We use both large context dependent (CD) and context independent (CI) models, as a method to investigate the dependency of the alignment on the system's configuration [START_REF] Adda-Decker | Pronunciation variants accros systems, languages and speaking style[END_REF]. 2. Automatic speech transcription experiments. The initial phonemic setting used for the ASR system includes 29 symbols: 20 consonants, 2 glides, 7 vowels and a special symbol for silence [START_REF] Vasilescu | Exploring pronunciation variants for romanian speech-to-text transcription[END_REF]. We evaluate the effect of the /1/-/2/ contrast on ASR performance, by comparing performance with and without the distinction. A weak contrast should result in a low word error rate increase 2 . Additionally, we consider two other vowel pairs proven to be frequent and to participate in morphological oppositions: [a]/[e] and [e]/[2] [START_REF] Renwick | The Phonetics and Phonology of Contrast: The Case of the Romanian Vowel System[END_REF]. The rationale behind this choice is that loss of the latter contrasts would increase the WER. Acoustic models are trained for each phone set using the respective pronunciation dictionaries in which the three vowels pairs are consecutively merged: [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF]/ [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF], [a]/[e] and [e]/ [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF]. The same mappings applied to pronunciation dictionaries used to automatically transcribe the data set. The training of the language models is as in [START_REF] Vasilescu | Exploring pronunciation variants for romanian speech-to-text transcription[END_REF]. All acoustic models are built in a semi-supervised manner as reported in [START_REF] Gauvain | Lightly supervised and unsupervised acoustic model training[END_REF][START_REF] Lamel | Development of a speech-to-text transcription system for finnish[END_REF] via flat start using about 370 hours of untranscribed audio. Acoustic models are triphone-based left-to-right 3-state Hidden Markov Models (HMM) with Gaussian mixture observation densities. The models are word position dependent. A neural network of 4 hidden layers with 10M parameters is trained with the cross-entropy criterion. The input consists of Perceptual Linear Predictive features [START_REF] Hermansky | Perceptual linear predictive (plp) analysis of speech[END_REF] with 9 spliced frame vectors. A Linear Discriminant Analysis transform is applied to reduce the input feature vector to 360. Constrained Maximum Likelihood Linear Regression [START_REF] Gales | Maximum likelihood linear transformations for hmmbased speech recognition[END_REF] speaker-dependent transforms are applied during training and testing. The target outputs consist of 10k HMM tied-states. 2 The commonly used metric for ASR systems evaluation is the Word Error Rate (WER), which takes into account three error types with respect to a reference transcription: substitutions of one word by another, insertions and deletions [START_REF] Lamel | Speech recognition[END_REF]. 5. Results

Frequency distribution

A frequency analysis illustrates which vowels are most common across the corpus, and which sounds tend to co-occur, setting the stage for calculations of functional load and mutual information. If two segments co-occur more often than predicted by their individual frequencies, phonological conditioning may be the cause. As shown in Figure 1, across the 9,032 distinct words in the corpus, [a], [e] and [i] are the most frequent timbres, whereas taken together [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] and [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] account for less than 10% of the vowels. These results are globally consistent with [START_REF] Renwick | The Phonetics and Phonology of Contrast: The Case of the Romanian Vowel System[END_REF], in particular with regard to the very low representation of the central vowels [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] and [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF]. The vowels [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] and [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] are the rarest elements of the system, despite their presence in frequent function words, and morphological role in the nominal and verbal declensions. Across the corpus their distribution is also highly complementary, as shown in Table 2: while [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] is common in word-initial position, [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] rarely appears there; conversely, [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] is common word-finally, in its role as a marker of nominal declension (e.g. ["fat2] 'girl' vs.

["fata] 'the girl') or verb form ([s2 "fak2], 'may he do it'); but [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] never appears finally. Within the CVC context where both appear, [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] overwhelmingly occurs before nasals or [r] (74.48% of CVC [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] tokens), due to its emergence as a product of pre-nasal raising [START_REF] Avram | [END_REF], while [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] can precede a wider range of segments ( [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] precedes [m,n,r] in 43.46% of CVC cases).

Functional load and contextual frequency

Although the central vowels are declared separate phonemes on the basis of minimal pairs like [r1u] 'river' vs. [r2u] 'bad', the fact that minimal pairs are very rare suggests that the functional load of their contrast is low -a situation that could account for the vowels' near-merger in continuous speech [START_REF] Renwick | A phonologically weak contrast can induce phonetic overlap[END_REF]. Results of these calculations are shown in the tables below; although either type or token frequency-based calculations are shown, results were similar using both measures.

As shown in Table 3, the functional load of the /2, 1/ contrast is the lowest of all pairwise comparisons, indicating that a minimal number of lexical contrasts would be lost if the two sounds merged. As for the Kullback-Leibler divergence, Tables 4 and 5 show that Kullback-Leibler divergence between /2, 1/ is the highest of all comparisons, based both on the lefthand and right-hand contexts for all vowel segments. This indicates that, more than any other vowel pair, these two appear in complementary environments. Finally the results for mutual information isolate certain contexts where either /2/ or /1/ is expected, for historical reasons (see Table 6). In those environments, there is considerable mutual information between the conditioned vowel and the context, and much less mutual information between the same context and the unconditioned vowel; for instance, the mutual information of /1/ with a preceding word boundary is high, while /2/ shares negative mutual information with the same context (and vice versa in word-final position).

Pronunciation variants for [1]

Introducing pronunciation variants in a recognizer system's lexicon may improve the system's performance [START_REF] Adda-Decker | Pronunciation variants accros systems, languages and speaking style[END_REF]. On the linguistic side, allowing an automatic selection of variants chosen to reflect contextual variation may validate and/or quantify the frequency of a phonetic event in connected speech [START_REF] Adda-Decker | Pronunciation variants in french: schwa and liaison[END_REF][START_REF] Vasilescu | Exploring pronunciation variants for romanian speech-to-text transcription[END_REF].

Here they are used to highlight the relationship between the canonical form as encoded in the pronunciation dictionary and the actual realizations of [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF]. The observed variation may match historical "footprints" (e.g. [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] aligned as [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] for an historical [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF]) and suggest ongoing mutations. Although with CI models more variants are selected, results show similar trends with both CI and CD models (Table 7): [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] is maintained or suppressed in word initial position before a nasal consonant, that is #VC context. Traditionally [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] in word initial position is associated with pre-nasal centralization, whereas word internal [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] corresponds to an emergence of [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] from [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF], originally as a contextually predictable allophone. In this ASR test, word internal position elicits maintenance, [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] selection, or suppression. Centralization effects (i.e. transcription of /1/ as [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF]) are evident for 10% of the occurrences with CI models and only 2% with CD models, and the difference can mainly be explained by the fact that CI models are much "wider" models and the system can more easily choose another phoneme. The CD models capture the local contexts of [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] and [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF], which is the likely explanation for why only 2% of lowering is observed. Taken together the results are consistent with analyses of [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF]'s historical emergence and restricted distribution [START_REF] Avram | [END_REF]. [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] were better recognized by the baseline system compared to the system where the two vowels were merged. As for merging [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF]/[1], 0.02% (14 words) are better recognized by the system when the opposition is reduced to a single symbol. These findings confirm the low relevance for the vocalic system of the /2/-/1/ contrast, as opposed to frequent and morphologically salient contrasts involving /e/-/a/ and /e/-/2/.

Discussion

We addressed the question of the marginal contrast between central vowels [START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] and [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] in Romanian. We applied a methodology based on frequency and functional load calculations, coupled to forced alignment and automatic speech transcription experiments, conducted on a 7 hour corpus of continuous speech. It has the advantage of not being dependent on the particular acoustic characteristics of the speech analyzed. Instead it permits estimation of the relevance of phonemic oppositions, within the lexicon and in their use in the language, because automatic speech recognition takes into account both distributional facts and acoustic distinctions. The results shows that /2/-/1/ is weakest contrast among the Romanian vowels. They are the least frequent, with the lowest functional load and with the highest score measured by the Kullback-Leibler divergence algorithm. The forced alignment of contextual variants for [START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] is consistent with historical and contrastive analysis of the sound's emergence and distribution. ASR experiments show that a 6vowel system where the /2/-/1/ contrast is removed by merging the two vowels performs as well as a classical 7-vowel system. More generally, this methodology shows how automatic transcription tools can help test phonological predictions using continuous speech. Further work concerns a more accurate investigation of the cognitive representations of the two vowels, through interative exploration and integration of data from phonological distributions, phonetic realization, and perception.

Figure 1 :

 1 Figure 1: Frequency distribution of the vowels. Left to right: /a, e, i, 1, o, u, 2/

Table 1 :

 1 Summary of data sources and characteristics

	Total sources	4
	Duration	7h10'
	Mean duration/file	4'56"
	Total words	56,296
	Total distinct words	9,032
	Speaker count	141

Table 2 :

 2 Distribution

		of the central vowels /1/ (î, â) and /2/ (ȃ)
	according to contexts where they appear. Examples of the most
	frequent word in each context are given.
	Ctx.	/1/	/2/
	CVC 30.5% România	26.6% astȃzi
	VVC	0.3% neîncadrabili	2.8% douȃ mii doisprezece
	CVV	1.3% mâine	1.8% sȃu
	#VC 67.2% în	0.4% ȃsta
	#VV	0.7% îi	0.1% ȃia
	CV#	0.0% -	65.8% sȃ
	VV#	0.0% -	2.5% douȃ

Table 3 :

 3 Functional load, calculated with respect to type fre-

	quency, change in entropy algorithm
	e	i	o	u	1	2
	a 0.0428 0.0143 0.0071 0.0135 0.0025 0.0456
	e	0.0257 0.0032 0.0107 0.0011 0.0545
	i		0.0018 0.0061 0.0007 0.0078
	o			0.0025 0.0011 0.0018
	u				0.0032 0.0036
	1					0.0004
	Table 4: Left-hand context comparison, Kullback-Leibler diver-
	gence; calculated with token frequency
	e	i	o	u	1	2
	a 0.901 1.087 1.151 0.815 4.359 1.132
	e	0.648 0.933 1.295 5.241 1.123
	i		1.648 0.802 4.006 1.770
	o			1.682 3.814 2.721
	u				3.354 2.198
	1					7.567
	Table 5: Right-hand context comparison, Kullback-Leibler di-
	vergence; calculated with token frequency
	e	i	o	u	1	2
	a 1.969 2.215 0.728 1.209 1.761 2.688
	e	1.207 1.253 1.519 4.061 2.442
	i		2.199 2.262 4.317 2.818
	o			0.567 2.366 1.936
	u				2.387 1.194
	1					5.430
	5.3. Assessing functionality through ASR experiments

Table 6 :

 6 Mutual information, calculated within ordered-pair bi-

	grams using token frequency
	Context	1	2	/1/ -/2/ Difference
	n	4.335	-1.139	5.474
	m	1.381	-1.007	0.374
	r	0.524	-1.43	1.954
	l	-1.141 -2.395	1.254
	#	2.481	-5.683	8.164
	#	-6.419	2.503	-8.922

Table 7

 7 by the[START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF]/[START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF] fusion. By contrast, 70% of words are affected by [e]/[a] and 59% by [e]/[START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF] fusion. The results in Table8highlight the correlation between relative frequency and functional load, and the the effect on ASR functionality.

	: Pronunciation variants for /1/ with CI (above) and CD
	(below) models. Word position: word initial (#VV, #VC and
	word internal (CVC, VVC, CVV), where V=/1/. Variants: main-
	tenance ([1]), suppression (∅), substitution ([2])
		CI models
	Word pos./var.	/1/	/2/	∅
	#VV	4	2	13
	#VC	709	138	564
	CVC	410	92	62
	VVC	3	0	1
	CVV	10	0	7
	Total	1136 (56%) 232 (10%) 647 (32%)
		CD models
	#VV	8	0	11
	#VC	1132	30	221
	CVC	516	11	20
	VVC	3	0	1
	CVV	15	1	0
	Total	1674 (85%)	42 (2%) 253 (12%)

5.3.2. Relating functional load to ASR results

In this experiment, four sets of acoustic models were tested: one including a classic vocalic inventory with 7 vowels and three in which each of the paired vowels (successively,

[START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF]

/

[START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF]

,

[a]/[e] and [e]/

[START_REF] Hualde | Quasi-phonemic contrasts in spanish[END_REF]

) are merged to a single symbol. In the data set, the pair [2]/

[START_REF] Scobbie | Quasi-phonemic contrast and the fuzzy inventory: Examples from scottish english[END_REF]

is the less represented: only 7% of words are affected

Table 8

 8

	: WER for baseline ASR system (7 vowels) compared to
	6-vowel systems ([2]/[1] vs. [e]/[a] vs. [e]/[2] fusion), and cal-
	culations of functional load and Kullback-Leibler divergence.
	rates	FL K-L right K-L left WER (%)
	baseline	-	-	-	15.4
	2/1	0.0004	5.43	7.56	15.5
	e/a	0.0428	1.96	0.90	16.8
	e/2	0.0545	2.24	1.12	16.0

http://www.quaero.org

Acknowledgements

This work was partially funded by the ANR VERA project (ANR 12 BS02 006 04). The authors are also grateful to Martine Adda-Decker for insightful comments and discussion.


D Chablat
email: damien.chablat@irccyn.ec-nantes.fr

Ph Wenger

J Merlet
email: merlet@sophia.inria.fr

WORKSPACE ANALYSIS OF THE ORTHOGLIDE USING INTERVAL ANALYSIS

Keywords: Optimal design, Parallel Mechanism, Machining, Workspace, Interval Analysis, Transmission factor

This paper addresses the workspace analysis of the orthoglide, a 3-DOF parallel mechanism designed for machining applications. This machine features three fixed parallel linear joints which are mounted orthogonally and a mobile platform which moves in the Cartesian x-y-z space with fixed orientation. The workspace analysis is conducted on the bases of prescribed kinetostatic performances. The interesting features of the orthoglide are a regular Cartesian workspace shape, uniform performances in all directions and good compactness. Interval analysis based methods for computing the dextrous workspace and the largest cube enclosed in this workspace are presented.

Introduction

Parallel kinematic machines (PKM) are commonly claimed to offer several advantages over their serial counterparts, like high structural rigidity, high dynamic capacities and high accuracy [START_REF] Treib | Similarity laws of serial and parallel manipulators for machine tools[END_REF][START_REF] Wenger | A Comparative Study of Serial and Parallel Mechanism Topologies for Machine Tools[END_REF]. Thus, PKM are interesting alternative designs for high-speed machining applications. This is why parallel kinematic machine-tools attract the interest of more and more researchers and companies. Since the first prototype presented in 1994 during the IMTS in Chicago by Gidding&Lewis (the Variax), many other prototypes have appeared.

However, the existing PKM suffer from two major drawbacks, namely, a complex Cartesian workspace and highly non linear input/output rela-tions. For most PKM, the Jacobian matrix which relates the joint rates to the output velocities is not constant and not isotropic. Consequently, the performances (e.g. maximum speeds, forces accuracy and rigidity) vary considerably for different points in the Cartesian workspace and for different directions at one given point. This is a serious drawback for machining applications [START_REF] Kim | Performance Analysis of Parallel Manipulator Architectures for CNC Machining Applications[END_REF][START_REF] Treib | Similarity laws of serial and parallel manipulators for machine tools[END_REF][START_REF] Wenger | A Comparative Study of Parallel Kinematic Architectures for Machining Applications[END_REF]. To be of interest for machining applications, a PKM should preserve good workspace properties, that is, regular shape and acceptable kinetostatic performances throughout. In milling applications, the machining conditions must remain constant along the whole tool path [START_REF] Rehsteiner | Putting Parallel Kinematics Machines (PKM) to Productive Work[END_REF][START_REF] Rehsteiner | Putting Parallel Kinematics Machines (PKM) to Productive Work[END_REF]. In many research papers, this criterion is not taking into account in the algorithmic methods used for the optimization of the workspace volume [START_REF] Luh | Working Capability Analysis of Stewart platforms[END_REF][START_REF] Merlet | Determination of 6D Workspace of Gough-Type Parallel Manipulator and Comparison between Different Geometries[END_REF]Ottaviano, (1991)).

The orthoglide is a 3-axis PKM with the advantages a classical serial PPP machine tool but not its drawbacks. It is an optimized version of the Delta mechanism defined by [START_REF] Clavel | Device for the Movement and Positioning of an Element in Space[END_REF]. Most industrial 3-axis machine-tool have a serial PPP kinematic architecture with orthogonal linear joint axes along the x, y and z directions. Thus, the motion of the tool in any of these directions is linearly related to the motion of one of the three actuated axes. Also, the performances are constant in the most part of the Cartesian workspace, which is a parallelepiped. The main drawback is inherent to the serial arrangement of the links, namely, poor dynamic performances.

The orthoglide is a PKM with three fixed linear joints mounted orthogonally. The mobile platform is connected to the linear joints by three articulated parallelograms and moves in the Cartesian x-y-z space with fixed orientation. Its workspace shape is close to a cube whose sides are parallel to the planes xy, yz and xz respectively. The interval analysis is conducted on the basis of prescribed bounded velocity and force transmission factors. Interval analysis based method is used to compute dextrous workspace as well as the largest cube enclosed in this workspace [START_REF] Merlet | ALIAS: an interval analysis based library for solving and analyzing system of equations[END_REF].

Description of the Orthoglide

Most existing PKM can be classified into two main families. The PKM of the first family have fixed foot points and variable length struts and are generally called "hexapods". The second family of PKM has been more recently investigated and have variable foot points and fixed length struts. PKMs of the second family are more interesting because the actuators are fixed and thus the moving masses are lower than in the hexapods and tripods.

The orthoglide studied in this article is a 3-axis translational parallel kinematic machine and is belongs to the second family. Figure 1 shows the general kinematic architecture of the orthoglide. The orthoglide has three parallel P RP aR identical chains (where P , R and P a stands for Prismatic, Revolute and Parallelogram joint, respectively). The actuated joints are the three orthogonal linear joints. These joints can be actuated by means of linear motors or by conventional rotary motors with ball screws. The output body is connected to the linear joints through a set of three parallelograms of equal lengths L = B i C i , so that it can move only in translation. The first linear joint axis is parallel to the x-axis, the second one is parallel to the y-axis and the third one is parallel to the z-axis. In figure 1, the base points A 1 , A 2 and A 3 are fixed on the i th linear axis such that

A 1 A 2 = A 1 A 3 = A 2 A 3 , B i
is at the intersection of the first revolute axis i i and the second revolute axis j i of the i th parallelogram, and C i is at the intersection of the last two revolute joints of the i th parallelogram. When each B i C i is aligned with the linear joint axis A i B i , the orthoglide is in an isotropic configuration and the tool center point P is located at the intersection of the three linear joint axes. In this configuration, the base points A 1 , A 2 and A 3 are equally distant from P . The symmetric design and the simplicity of the kinematic chains (all joints have only one degree of freedom, fig. 2) should contribute to lower the manufacturing cost of the orthoglide. The orthoglide is free of singularities and self-collisions. The workspace has a regular, quasi-cubic shape. The input/output equations are simple and the velocity transmission factors are equal to one along the x, y and z direction at the isotropic configuration, like in a serial P P P machine [START_REF] Wenger | A Comparative Study of Parallel Kinematic Architectures for Machining Applications[END_REF].

Kinematic Equations and Singularity Analysis

We recall briefly here the kinematics of the Orthoglide (See Wenger and Chablat, 2001 for more details).

Kinematic Equations

Let θ i and β i denote the joint angles of the parallelogram about the axes i i and j i , respectively (fig. 2). Let ρ 1 , ρ 2 , ρ 3 denote the linear joint variables, ρ i = A i B i and L denote the length of the tree legs, B i C i . The position vector p of the tool center point P is defined in a reference frame (O, x, y, z) centered at the intersection of the three linear joint axes (note that the reference frame has been translated in Fig. 1 for more legibility).

Let ρ be referred to as the vector of actuated joint rates and ṗ as the velocity vector of point P :

ρ = [ ρ1 ρ2 ρ3 ] T , ṗ = [ ẋ ẏ ż] T
ṗ can be written in three different ways by traversing the three chains

A i B i C i P : ṗ = n 1 ρ1 + ( θ1 i 1 + β1 j 1 ) × (c 1 -b 1 ) (1a) ṗ = n 2 ρ1 + ( θ2 i 2 + β2 j 2 ) × (c 2 -b 2 ) (1b) ṗ = n 3 ρ3 + ( θ3 i 3 + β3 j 3 ) × (c 3 -b 3 ) (1c)
where b i and c i are the position vectors of the points B i and C i , respectively, and n i is the direction vector of the linear joints, for i = 1, 2,3.

B 1 i 1 P x z y j 1 A 1 C 1 A 2 B 2 C 2 A 3 C 3 B 3 Figure 1. Orthoglide kinematic architecture i i j i r i P q i b i B i A i C i L Figure 2. Leg kinematics

Singular configurations

We want to eliminate the two idle joint rates θi and βi from Eqs. (1ac), which we do upon dot-multiplying Eqs. (1a-c) by c ib i :

(c 1 -b 1 ) T ṗ = (c 1 -b 1 ) T n 1 ρ1 (2a) (c 2 -b 2 ) T ṗ = (c 2 -b 2 ) T n 2 ρ2 (2b) (c 3 -b 3 ) T ṗ = (c 3 -b 3 ) T n 3 ρ3 (2c)
Equations (2a-c) can now be cast in vector form, namely

A ṗ = B ρ
where A and B are the parallel and serial Jacobian matrices, respectively:

A =    (c 1 -b 1 ) T (c 2 -b 2 ) T (c 3 -b 3 ) T    and B =   η 1 0 0 0 η 2 0 0 0 η 3   (3) with η i = (c i -b i ) T n i for i = 1, 2, 3.
Parallel singularities [START_REF] Chablat | Working Modes and Aspects in Fully-Parallel Manipulator[END_REF] occur when the determinant of the matrix A vanishes, i.e. when det(A) = 0. In such configurations, it is possible to move locally the mobile platform whereas the actuated joints are locked. These singularities are particularly undesirable because the structure cannot resist any force. Eq. (3a) shows that the parallel singularities occur when:

(c 1 -b 1 ) = α(c 2 -b 2 ) + λ(c 3 -b 3 )
that is when the points B 1 , C 1 , B 2 , C 2 , B 3 and C 3 are coplanar. A particular case occurs when the links B i C i are parallel:

(c 1 -b 1 )//(c 2 -b 2 ) and (c 2 -b 2 )//(c 3 -b 3 ) and (c 3 -b 3 )//(c 1 -b 1 )
Serial singularities arise when the serial Jacobian matrix B is no longer invertible i.e. when det(B) = 0. At a serial singularity a direction exists along which any cartesian velocity cannot be produced. Eq. (3b) shows that det(B) = 0 when for one leg i,

(b i -a i ) ⊥ (c i -b i ).
When A and B are not singular, we obtain the relations, ṗ = J ρ with J = A -1 B (4)

Velocity transmission factors

For joint rates belonging to a unit ball, namely, || ρ|| ≤ 1, the Cartesian velocities belong to an ellipsoid such that: ṗT (JJ T ) ṗ ≤ 1

The eigenvectors of matrix JJ T define the direction of its principal axes of this ellipsoid and the square roots ψ 1 , ψ 2 and ψ 3 of the eigenvalues σ 1 , σ 2 and σ 3 of JJ T , i.e. the lengths of the aforementioned principal axes are the velocity transmission factors in the directions. To limit the variations of this factor in the Cartesian workspace, we set

ψ min ≤ ψ i ≤ ψ max (5)
throughout the workspace. To simplify the problem, we set ψ min = 1/ψ max where the value of ψ max depends on the performance requirements.

Determination of the dextrous workspace

The dextrous workspace W is here defined as the loci of the points for which all the eigenvalues of the matrix JJ T , i.e. the velocity transmission factors, lie within a predefined range [σ min , σ max ]. These eigenvalues are determined by solving the third degree characteristic polynomial of the matrix which is defined only for the points within the intersection I of the three cylinders defined by

x 2 + y 2 ≤ L x 2 + z 2 ≤ L y 2 + z 2 ≤ L (6)
To solve numerically the above equations, the length of the legs is normalized, i.e. we set L = 1. Our purpose in this section is to determine an approximation of W as a set of 3D Cartesian boxes for any point of which we are sure that the constraints on the eigenvalues are satisfied. The width of all the boxes in the list will be greater than a given threshold and the value of this threshold will define the quality of the approximation.

Box verification

A basic tool of the algorithm is a module M(B) that takes as input a box B belonging to I and whose output is: either that for any point in the box the eigenvalues lie in the range [σ min , σ max ] or that for any point in the box one of the eigenvalues is either lower than σ min or larger than σ max or that the two previous conditions does not hold for all the points of the box i.e. that for some points the eigenvalues lie in the range [σ min , σ max ] while this is not true for some other points

The first step of this module consists in considering an arbitrary point of the box (e.g. its center) and to compute the eigenvalues at this point: either all of them lie in the range [σ min , σ max ] or at least one of them lie outside this range.

In the first case if we are able to check that there is no point in B such that the eigenvalue at this point may be equal to σ min or σ max , then we may guarantee that for any point of B the eigenvalues will be in the range [σ min , σ max ]. Indeed assume that at a given point of B the lowest eigenvalue is lower than σ min : this implies that somewhere along the line joining this point to the center of the box the lowest eigenvalue will be exactly σ min . To perform this check we substitute in the polynomial λ successively by σ min and σ max to get a polynomial in x, y, z only. We have now to verify if there is at least one value for these three variables that cancel the polynomial, being understood that these values have to define a point belonging to B: this is done by using an interval analysis algorithm from the ALIAS library [START_REF] Merlet | ALIAS: an interval analysis based library for solving and analyzing system of equations[END_REF].

Assume now that at the center of the box the largest eigenvalue is greater than σ max . If we are to determine that there is no point of B such that one of the eigenvalue is equal to σ max , then we may guarantee that for any point of B the largest eigenvalue will always be greater than σ max . This check is performed by using the same method than in the previous case. Hence the M module will return:

1: if for all points of B the eigenvalues lie in [σ min , σ max ] (hence B is in the dextrous workspace) -1: if for all points of B either the largest eigenvalue is always greater than σ max or the lowest eigenvalue is lower than σ min (hence B is outside the dextrous workspace). 0: in the other cases i.e. parts of B may be either outside or inside the dextrous workspace

4.2

Algorithm for the determination of the dextrous workspace

The principle of the algorithm is pretty simple: we will maintain a list L of boxes, indexed by i, which is is initialized with the box [-1,1], [-1,1], [-1,1]. A minimal width ǫ for the ranges in a box is defined and the operator W(B i ) will return the largest width of the ranges in B i . An error index E will be computed as the total volume of the boxes that are not in the approximation but may contain points that are inside the dextrous workspace. We then apply M(B i ):

if M(B i )=1: we store B i as part of the dextrous workspace and consider the next box in

L if M(B i )=-1: we consider the next box in L if M(B i )=0: -if W(B i ) ≥ ǫ:
we create 2 new boxes from B i by bisecting the range of B i with the largest width. The two new boxes are put at the end of L otherwise we add the volume of B i to E

The algorithm stops when all the boxes in L have been processed. Note that this basic algorithm has to be modified in order to consider only boxes that belongs to I but this can be done using the same principle.

The algorithm returns a description of the dextrous workspace as a list of boxes and the comparison between the volume of the approximation and E allows to determine the quality of the approximation. Note that E is very conservative as part of this volume consists in points that do not belong to I or to the dextrous workspace.

Implementation and results

The previous algorithms has been implemented in Maple with a system call to a C++ program that implements the M module. For an ǫ of 0.05 we found in about 5 hours that the volume of the dextrous workspace is 1.468 with an error bound of [0,0.48] with σ min = 0.25 and σ max = 4, i.e. ψ min = 1/2 and ψmax = 2 (Fig. 3).

5.

Determination of the largest cube enclosed in the dextrous workspace

For usual machine tools, the Cartesian workspace is generally given as a function of the size of a right-angled parallelepiped. Due to the symmetrical architecture of the orthoglide, the Cartesian workspace has a fairly regular shape in which it is possible to include a cube whose sides are parallel to the planes xy, yz and xz respectively (Fig. 4). We will now describe a method for determining a cube that is enclosed in this workspace whose edge length is 2R such that there is no other cube enclosed in the workspace with an edge length of 2(R + α), where α is an accuracy threshold fixed in advance.

The first step is to determine the largest cube enclosed in the workspace with a center located at (0,0,0). This is done by using the M module on the box

[-A -kα, A + kα], [-A -kα, A + kα], [-A -kα, A + kα]
where k is an integer initialized to 1 and A a number initialized to 0.

Each time the M module returns 1 (which means that the cube with edge length 2(A + kα) is enclosed in the dextrous workspace) we set A to A + kα and we double the value of k. When this module returns -1 if k is greater than 1 we reset k to 1 and restart the process, otherwise the process stops and we have determined that the cube with edge length 2A is enclosed in the workspace while the cube with edge length 2(A + α) is not: thus A is an initial value for R.

We use then the same algorithm than for the determination of the workspace with the following modifications:

for each box B i in L we test if at the 8 corners of the cube centered at the center of the box and with edge length 2(R + α) the eigenvalues satisfies the constraints:

if this not the case let u be the maximal half-width of the ranges of B i and assume that u 1 = R -u > 0. If for at least for one corner of the cube C with center of B i and edge length u 1 the eigenvalues do not satisfy the constraint, then the center of the largest cube cannot be located in B i : indeed any cube with a center in B i and edge length 2R will include all the corners of C and thus contain at least a point for which the eigenvalues do not satisfy the constraints.

if at the corners the eigenvalues are all valid then we search for the largest cube centered at the center of the box using the same method than for the determination of the largest cube centered at (0,0,0). If we find a cube with a larger edge length than 2R, then the value of R is updated.

the boxes are bisected only if the largest width of their ranges is greater than 2α: indeed even if the largest cube has a center located in such box, then the maximal edge length will be at most 2(R + α).

Using this algorithm with a value of 0.001 for α we found out that the largest cube has its center located at (0.085938, 0.085938, 0.085938) and that its edge length was L W orkspace = 0.643950 while we may guarantee that there is no cube with edge length larger than 0.643952 enclosed in the workspace

Conclusions

The dextrous Cartesian workspace and the largest cube enclosed in this workspace is computed using interval analysis based method for the Orthoglide. Unlike most existing PKMs, the dextrous workspace is fairly regular and the performances are homogeneous in it. Thus, the entire workspace is really available for tool paths. The bounds of velocity and force transmission factors used in this paper are given as an example because it depends on the performance requirements for machining applications. A 1:3-scale prototype of this mechanism is under construction in our laboratory with these bound contraints.

Figure

  Figure 3. Dextrous workspace of the Orthoglide mechanism

Figure 4 .

 4 Figure 4. Cartesian workspace and isotropic configuration of the Orthoglide mechanism


Marie Gaille

Ruth Horn

The role of 'accompagnement' in the end-of-life debate in France: from solidarity to autonomy

Keywords: autonomy, solidarity, end of life, international bioethics, palliative care, accompagnement, France

This paper traces the way autonomy has become a recognised value in health care in France. In a country which based for many years its social fundamentals on the very idea of solidarity, autonomy has long been considered a foreign ‗Anglo-American principle'. Taking the example of the end-of-life debate, the paper shows however how the use of the French term ‗accompagnement' allowed to redefine autonomy and to associate it with the leading moral principle of solidarity. Exploring the arguments used over the past 25 years in professional guidelines, parliamentary reports, ethics committee reports, and legal texts, the authors describe the shift that had happened in public and legal discourses on end-of-life care. The analysis demonstrates how the scope of autonomy had to be limited by other social values such the protection of the dying person, in order to become an accepted social value in its own. The example of the French end-of-life debate shows that depending on how the concept of autonomy is adapted and applied in a specific context, it can be compatible with the idea of solidarity. Such compatibility has been challenged previously in the international bioethics debate. By demonstrating the possibility of combining autonomy and solidarity, this paper makes an important contribution to the international bioethics debate and to the dialogue between countries that are often perceived as significantly different.

Introduction

Continental European and Anglo-Saxon approaches to healthcare are often opposed to describe two conceptions of care: in continental European countries, solidarity appears to be the core value of healthcare systems, whereas a rights-based individualistic conception seems to prevail in Anglo-Saxon countries. The prominence of solidarity in the continental approach is often considered as detrimental to the respect of patient autonomy and seen as compatible with paternalistic relationships. We challenge this opposition, first, because both autonomy and solidarity are notions that can have various meanings; second, because the notion of solidarity can make a meaningful contribution to the theoretical debate on autonomy and vice versa. In this paper, we use the end-of-life debate in France as a case-study that shows how autonomy and solidarity can be combined. As we will see, this combination allows seeing the individual as a related being, rather than an atomistic subject.

Since its emergence in the late 1970s, the end-of-life debate in France has become more intense and radical. 1 From the 1990s onwards, this development has been demonstrated by the increase in the number of end-of-life cases reported in the media, and by more frequent discussion of the issues in professional, political and legal medical discourses [START_REF] Baud | Le droit de vie et de mort -archéologie de la bioéthique[END_REF][START_REF] Castra | Bien mourirsociologie des soins palliatifs[END_REF][START_REF] Memmi | Faire vivre et laisser mourirle gouvernement contemporain de la naissance et de la mort[END_REF][START_REF] Gaille | La valeur de la vie[END_REF][START_REF] Horn | Le droit de mourirchoisir sa fin de vie en France et en Allemagne[END_REF][START_REF] Horn | ‗I don't need my patients' opinion to withdraw treatment': patient preferences at the end-of-life and physician attitudes towards advance directives in England and France[END_REF]. This change is of particular interest for ethical and political analysis. As some philosophers and social scientists have observed, controversies that arise at the patient's bedside and in the legal and political context reflect values and principles that are dominant in a specific context [START_REF] Isambert | Contraception et avortement: Dix ans de débat dans la presse (1965-1974[END_REF][START_REF] Gautier | L'ordinaire et le politique[END_REF][9][10].

In the past 25 years, the French end-of-life debate has undergone a significant shift from a solidarity-or community-oriented to a more autonomy-based approach. As we will show, the notion of autonomy was considered initially as a foreign ‗Anglo-American' concept and was regarded with scepticism. Autonomy was presented as an antonym to ‗solidarity', an idea which was taken for granted and could easily be used to justify end-of-life practices. Increasingly however, the notion of autonomy began to emerge in French medical ethics and in the legal discourse. Ultimately, it became an important and socially accepted value that was no longer questioned. Currently, an attempt is being made to ‗reconcile' the notions of autonomy and solidarity. We will illustrate this attempt through the analysis of the use of the French term 'accompagnement' which could best be translated by ‗support' or ‗presence'. This term is used in ordinary French language, but has gained a normative connotation in medical practice.

In this paper, we discuss the use of and the meaning attributed to the notions of solidarity and autonomy in the French end-of-life debate. Our aim is a better understanding of this specific debate, in order to highlight its interest for the international bioethics debate. Values, norms and principles are often used and defined in many different ways. As Garcia noticed, the notion of autonomy has ‗many faces' [START_REF] Garcia | The many faces of autonomy[END_REF]. It is the same for the notion of solidarity [START_REF] Jaeggi | Solidarity in Health and Social Care in Europe[END_REF][START_REF] Häyry | European values in bioethics: Why, what, and how to be used[END_REF].

We will discuss whether and how their meanings have been adapted to meet goals and needs that are specific to the French debate.

Our analysis focuses on public and legal discourses. From a methodological point of view, we will examine a series of texts that are exemplary for the public and legal debate, such as professional guidelines, parliamentary reports, ethics committee reports, and legal texts. Our examination aims to identify: 1. the ethical problems perceived with regard to the end-of-life in France; 2. the way medical practice and social attitudes have developed in the course of the debate; 3. the way moral and legal legitimacy of end-of-life practices is achieved.

We will first show how autonomy and solidarity became part of the moral reflection about medical decision making in France (paragraph 1). We will then examine how the notion of autonomy has found its place in the debate about end-of-life care up to the present (paragraph 2). Finally, we will present an analysis of the moral scope and limits of the shift towards a combination of solidarity and autonomy in the French end-of-life debate (paragraph 3).

Solidarity and autonomy in the French health care debate

Both autonomy and solidarity are key notions in the French end-of-life debate, as well as in other debates about ‗good' medical practice, e.g. regarding assisted reproduction. The importance of these two notions in the end-of-life debate is the result of a complex history.

Tracing back this development allows us to understand how this debate took shape, and which normative arguments were employed. It also highlights the specific meaning and use of the notions of autonomy and solidarity in the end-of-life debate.

As a first step, we will discuss the meaning of solidarity. Despite the association that can be made with the idea of obligatio in solidum in Roman law or with that of the Republican principle of concordia or the Christian fraternitas, ‗solidarity' is a modern term. The term ‗solidarity' appeared in dictionaries only at the end of the 18th century and was first used in a legal context in Europe. Following the French Revolution, the term was employed in political theories in order to combine the principle of individual liberty with the idea of social cohesion and community [START_REF] Brunkhorst | Solidarity -From Civic Friendship to a Global Legal Community[END_REF]. This idea was taken up and developed by the founding fathers of sociology, Auguste Comte and Emile Durkheim. Despite the fact that the term solidarity emerged in the context of the French Revolution, it spread across Europe and took on different meanings [START_REF] Kapeller | The grounds of solidarity: From liberty to loyalty[END_REF][START_REF] Sternjø | Solidarity in Europe, The History of an idea[END_REF]. The multiple meanings associated with solidarity may have contributed to its negative connotation as a ‗wishy-washy concept' [START_REF] Jaeggi | Solidarity in Health and Social Care in Europe[END_REF] or a purely ‗rhetorical idea' that is interchangeable with other terms such as ‗fraternity', ‗brotherhood', ‗community' or ‗unity' [START_REF] Brunkhorst | Solidarity -From Civic Friendship to a Global Legal Community[END_REF][START_REF] Wilde | The concept of solidarity: emerging from theoretical shadows ?[END_REF].

In France however, the notion of solidarity always occupied a prominent place, notably in the development of the healthcare system. Already prior to the French Revolution, ‗hospitals' or ‗hospices' were established to receive poor and sick people, old persons, young orphans or abandoned children. During the Revolution, this policy, based on the principle of solidarity, was reinforced with the introduction of a publicly-funded system, the ‗assistance publique'.

From the late 19th century onwards until World War II, several laws enabled access to medical care in public hospitals for more and more types of sick people. In 1945, the establishment of the social security system gave universal access to hospital care. Based on the principle of ‗solidarity', every French citizen should enjoy equal access to the health care system, regardless of their income and origin [START_REF] Rochaix | Contribution à l'étude des problèmes hospitaliers contemporains[END_REF][START_REF] Hatzfeld | Du paupérisme à la Sécurité sociale 1850-1940[END_REF][START_REF]Histoire des hôpitaux en France[END_REF][START_REF] Dodier | L'admission des malades[END_REF][START_REF] Valat | Histoire de la sécurité sociale (1945-1967[END_REF][START_REF] Gaille | Anthropologie médicale et pensée politique[END_REF].

In the French context, solidarity has two meanings; firstly, it implies the public organisation of the health care system, as opposed to an organisation exclusively based on private structures and charity funds; secondly, it suggests a bond between the members of society, who must help each other through hardship. It has a normative meaning and describes a type of ‗non-instrumental cooperation' [START_REF] Jaeggi | Solidarity in Health and Social Care in Europe[END_REF]. To a certain extent, during the course of French history, ‗solidarity' became part of daily language, a term that needed no further definition.

Yet, as we will show through the example of the end-of-life debate, its meaning could change depending on circumstances and political or social motivations.

The emergence of the notion of ‗autonomy', in terms of patient autonomy, relates to recent history. In France as well as in other Western societies, patient autonomy has three meanings [START_REF] Ménoret | La prescription d'autonomie en médecine[END_REF]. It was first recognised as a goal of medicine which aimed to restore bodily functions.

Medical teams speak still today of ‗functional autonomy', in relation to the physical capacities of the patient. Then, following the increasing prevalence of chronic disease due to early detection and improved treatment (e.g. the discovery of insulin in 1921), the idea of patient autonomy also took on the sense of patient self-management. Finally, since the Nuremberg trials in 1947, respect for patient autonomy became a prevailing, ethical principle, in order to regulate human experimentation and medical decisions at the bedside. As Sade pointed out, ‗one of the earliest projects of bioethics was to promote patient autonomy, in an effort to counter the paternalistic decision-making by physicians that was so deeply embedded in medical practice before the 1960s' [START_REF] Sade | Autonomy and Beneficence in an Information Age[END_REF]. In the history of bioethics, this idea has at least two dimensions: it relates to patient privacy and to self-determination.

In France, the criticism of the paternalistic model developed in the 1970s within philosophy and social sciences, noticeably in the works of Canguilhem and Illich; it was reinforced by the early translations of Goffman and Freidson [START_REF] Bureau | Les patients contemporains face à la démocratie sanitaire[END_REF]. The rejection of the paternalistic approach was triggered by the development of the HIV patient movement. These patients did not want to be considered as « vulnerable » patients any more, but as competent persons able to make decisions about their own lives and their participation in research protocols [START_REF] Callon | Le Pouvoir des malades[END_REF][START_REF] Barbot | Les Malades en mouvements[END_REF][START_REF] Dodier | Leçons politiques l'épidémie de sida[END_REF][START_REF] Amiel | Des cobayes et des hommes[END_REF]. From the 1980s, this criticism of the paternalistic model was also based on various issues extensively covered by the daily press, such as the contaminated blood scandal from the 1980s to the 1990s or cases of chemical pollution [START_REF]Toxic World. Toxicants, Health and Regulation in the XXth Century[END_REF][START_REF]Powerless Science? The Making of the Toxic World in the Twentieth Century[END_REF][START_REF] Torny | De la réparation individuelle à l'élaboration d'une cause collective : L'engagement judiciaire des victimes du distilbène[END_REF]. These events had two consequences: first of all, ‗trust' in medicine and in the public health system significantly decreased; secondly, from the 1980s on, French citizens were very concerned to reform the law about medical decisionmaking. O. O'Neill's analysis of trust and autonomy shows a good grasp of the issues at stake in this debate [START_REF] O'neill | Autonomy and Trust in Bioethics[END_REF].

However, the criticism of the paternalistic approach and the shift towards a ‗democracy in health-care' (démocratie sanitaire) did not entail a consensual acceptance of the idea of patient autonomy in France. Patient self-determination was considered with suspicion, and still is, up to a certain extent. Autonomy was not necessarily considered as a good in itself and the protection of the ‗vulnerable' patient seemed to be more important.

Today, we observe that the French health care system is evolving towards a patient-centred approach and is beginning to take on board the idea of shared decision-making. Special attention is paid to the issue of patient autonomy in more cases in which patients appear unable to make decisions for themselves [START_REF] Noirot | Refus d'assistance des sans-abri. Psychopathologie et éthique : liberté ou interventionnisme ?[END_REF][START_REF] Ayraud | Quelle autonomie pour les ‗incapables' majeurs ? Déshospitalisation psychiatrique et mise sous tutelle[END_REF][START_REF] Béliard | ‗C'est pour son bien'. La décision pour autrui comme enjeu micro-politique[END_REF][START_REF] Galès | Alzheimer, préserver ce qui importe, les capabilités dans l'accompagnement à domicile[END_REF]. However, many studies stress the limits of this development in French medical practice and some scholars object that the new ‗patientcentredness' is only ‗rhetorical' [START_REF] Fainzang | An Anthropology of Lying: Information in the Doctor-Patient Relationship[END_REF][START_REF] Baszanger | Une autonomie incertaine : les malades et le système de soins[END_REF][START_REF] Thouvenin | La loi no 2005-370 du 22 avril 2005, dite loi Leonetti: la médicalisation de la fin de vie[END_REF][START_REF] Klein | Contribution à l'histoire du « patient » contemporain. L'autonomie en santé : du self-care au biohacking[END_REF][START_REF] Bureau | Les patients contemporains face à la démocratie sanitaire[END_REF].

The end-of-life debate plays a key role in the discussion about the understanding and acceptance of autonomy in French health care. In the following section, we will focus on how ambiguity with regard to patient autonomy influences public documents and law.

The French end-of-life debate and its 'struggle' with autonomy

Since the beginning of the end-of-life debate in France in the 1980s, professional guidelines, committee reports, and laws are evidence of the difficulty of employing the notion of autonomy. Although paternalism has been increasingly criticised in the public and professional discourse, respect for autonomy is still finding a place in the debate. In addition to a persisting paternalism, we also observe tensions between a certain understanding of patient autonomy (in terms of self-determination) and the arguments used by proponents of palliative care, in order to challenge a patient's request to die.

Palliative care developed in France from the 1980s onwards, but, in contrast to other countries, the expression ‗hospice movement' never became established there; the expression ‗palliative care and accompagnement' was used instead [START_REF] Horn | Le droit de mourirchoisir sa fin de vie en France et en Allemagne[END_REF]. Along with the development of palliative care in France, the term ‗accompagnement' gradually gained in importance in the end-of-life debate. Proponents of palliative care argued that requests for the right to die do not necessarily express autonomous wishes, but rather the fear of dying alone and abandoned by society. They claimed that patients at the end of life needed to be supported by their doctors and carers even when no further treatment is available [START_REF] Horn | Le droit de mourirchoisir sa fin de vie en France et en Allemagne[END_REF]. The focus of the palliative care movement was, and still is today, on support of the dying patients and their loved ones.

In a response to an increasingly vehement and polarised right-to-die debate, the French government opted to focus on the development of palliative care in the public health care system. In 1986, a regulatory text, the circulaire Laroque, stated that patients at the end of life should be taken in charge by palliative care teams, who would support the person in their final days and respond to their physical, psychological, spiritual and social needs [START_REF]3D du 26 août 1986 relative à l'organisation des soins et à l'accompagnement des malades en phase terminale. 44[END_REF]. A few years later, a law was passed in 1991 requiring the provision of palliative care and ‗accompagnement' by the public health care system [44]. Several parliamentary reports emphasised however the lack of structures guaranteeing the support of end-of-life patients and a subsequent law was passed in 1999 [45]. This law established a right to palliative care and ‗accompagnement', and a right to oppose medical examinations and therapeutic interventions.

Physicians however were not legally hold to respect such an opposition.

Whereas the notion of ‗accompagnement' emphasises that the dying patient is a person with individual needs and values, the focus on autonomy could not serve to justify respect for patients' wishes in the French debate. The notion of ‗accompagnement' implies the patient's embeddedness in society, rather than putting the focus on their individuality: medical teams, and society at large, function as an active and supportive presence in the last moments of life.

During this time, the notion of ‗solidarity' was rarely employed in the debate. It was mainly understood as a notion relevant to political and legal debates, and although it was presented as a core value of the French health care system, it was not part of the usual categories of ethical reflection about medical decision-making at the bedside. However, it was used once to argue in favour of a law on ‗euthanasia' in exceptional cases; this was in a report of the French national ethics committee (CCNE) in 2000 [START_REF]Fin de vie, arrêt de vie, euthanasie. Avis[END_REF]. In this report, the CCNE discusses the challenges of end-of-life care in the light of technical developments and changing society.

The report emphasises the importance of supporting patients in the final stage of life and of taking into account their individual wishes, beliefs and needs, rather than insisting on futile treatment. The committee presents palliative care as an answer to difficult end-of-life situations. However, the CCNE admits that in the exceptional case of unmanageable pain, or where patients are dependent on life support and deprived of their relational capacities, their wish to die should be granted. According to the committee, such situations of distress require society's ‗human solidarity and compassion' and justify the ‗exceptional practice of euthanasia'. The committee's report was widely debated in French society, yet it had no impact on legislation.

Nevertheless, at this moment, patient rights were increasingly under discussion in France and became the subject of legal reforms. Normative reflection entered a new phase. While some scholars still argued that autonomy was an inappropriate ethical principle on which to base the care of ‗vulnerable patients' [START_REF] Pelluchon | Loi 2002-303 du 4 mars 2002 relative aux droits des malades et a`la qualite´ du syste`me de sante´[END_REF], others argued that autonomy could no longer be ignored.

Despite the ongoing ambivalence towards autonomy, in 2002, a law was passed to enforce the rights of patients e.g. their right to refuse treatment [48]. However, in 2003, the case of Vincent Humbert, a paraplegic patient who claimed his right to die, highlighted the uncertainties of physicians regarding the legality of withdrawing life-supporting treatment such as clinically-assisted hydration and nutrition [START_REF] Horn | Le droit de mourirchoisir sa fin de vie en France et en Allemagne[END_REF]. This case attracted much media attention and generated, among other things, an important parliamentary report in 2004 [START_REF]Rapport no 1708[END_REF] and a report by the CCNE in 2005 [START_REF]Refus de traitement et autonmie de la personne[END_REF]. Both reports stressed the need to improve the support of end-of-life patients and to reassure physicians of the legality of withdrawing even lifesustaining treatment. The CCNE's report presents an ambiguous argument regarding refusal of treatment by a patient. Although the committee's aim was to define a solid ethical argument justifying treatment refusal, it tended to emphasise such situations in which refusals should be challenged: e.g., cases of cognitively impaired patients, addicted patients, or patients who suffer from psychiatric disorders or emotional distress. Finally, using the same arguments as palliative care supporters, the CCNE report states that refusal of treatment sometimes expresses a call for help and should understood as such by the medical team.

Following the discussions around the Humbert case, a new law was passed in 2005 [51]. This law explicitly introduced the right to refuse ‗every' treatment including clinically-assisted nutrition and hydration, and defined the physician's right to withdraw treatment at the end of life. This law clearly defined physicians' ‗right to let a patient die' and their obligation to maintain the quality of life and the dignity of the dying person. The law also promoted the development of palliative care. Although the law of 2005 aimed to strengthen the respect for patient autonomy, it was also evidence of ambivalence towards that autonomy. Firstly, it was only applicable to ‗competent' patients. Secondly, it stated that the physician should ‗do all that is possible in order to persuade the patient to continue the treatment, when the refusal endangered the patient's life; and the patient was required to repeat their wish to discontinue treatment. As the legal scholar Thouvenin pointed out, in a clause that establishes a patient's subjective right, in other words, that defines the patient as the right-holder, such limitation appears to be a paradox [START_REF] Thouvenin | La loi no 2005-370 du 22 avril 2005, dite loi Leonetti: la médicalisation de la fin de vie[END_REF]. This paradox, or the struggle to respect patient autonomy, also showed in the value attributed to advance directives to refuse treatment in cases where the patient is no longer able to express their wishes. Until 2016, advance directives only had advisory value in French law.

The law of 2005 stated that the physician may take these documents into account but is not obliged to respect them. As Horn has shown, advance directives have long been considered as individualistic ‗Anglo-Saxon inventions' that have no place in France, ‗a country with social values' [START_REF] Horn | ‗I don't need my patients' opinion to withdraw treatment': patient preferences at the end-of-life and physician attitudes towards advance directives in England and France[END_REF]. The parliamentary report of 2004 argued that according binding value to ADs could weaken both the family's and the physician's sense of responsibility for the patient's physical welfare, as well as their solidarity with the vulnerable person [START_REF]Rapport no 1708[END_REF].

From the very beginning, the 2005 law was discussed as a provisional legal framework.

Several cases which were discussed in the media showed its limitations in addressing the following: patients' needs for effective pain management at the end of life (case of Hervé Pierra); their requests for a self-determined death (case of Chantal Sébire); and the procedures required to withdraw treatment at the end of life, in the case of conflict of opinion (case of Vincent Lambert). A parliamentary report of 2008 confirmed the shortcomings of the law and its application in medical practice [51].

The French president François Hollande set up a consultation in order to review the law. This resulted in a new report being published by a parliamentary committee in 2012 [START_REF] Sicard | Penser solidairement la fin de vie -Commission de réflexion sur la fin de vie en France[END_REF]. This report, entitled ‗Reflections on the end of life from a perspective of solidarity' (Penser solidairement la fin de vie) made two suggestions, in particular on how to improve the law on end-of-life treatment: firstly, the report suggested granting greater value to advance directives, i.e. strengthening patient autonomy. Secondly, and as a ‗French solution' to problems regarding the respect for patient wishes, the report suggested improving the support ('accompagnement') of dying patients. According to the report, palliative care should be provided from the very moment the patient is diagnosed with a serious illness, and continuous deep sedation should be offered at the request of patients deciding to discontinue lifesustaining treatment, e.g. clinically-assisted nutrition and hydration. The report of 2012 illustrates a new and growing use of the term ‗accompagnement' promoting both solidarity and autonomy. This term, so long associated with palliative care, expresses the duty of society towards dying patients and their loved ones, a duty which implies a confrontation with death, a fight against the feeling of abandonment and loneliness and finally, equal access to palliative care. ‗Accompagnement' has long been an expression of solidarity. The report of 2012 also refers to solidarity but includes respect for autonomy as a new element in the ‗accompagnement' of dying patients. The word ‗accompagnement' is not precisely defined in this report. However, this text indicates that ‗accompagnement' has become a central theme in the reflection about end-of-life care. According to the report, ‗accompagnement' is considered as necessary in order to cope with the fear of abandonment and the anxiety of dying felt by many patients. It is also seen as an important element to encourage people to openly discuss end-of-life issues. At a political level, social inequalities in access to end-of-life care and support for proxies must also be dealt with. Finally, ‗accompagnement' is also associated with an attitude of respect for patient wishes. This aspect relates ‗accompagnement' to patient autonomy since the report rejects decisions that do not take into account the patient's view.

For these reasons, ‗accompagnement' appears as the leading principle of a society that takes care of dying patients. In this report, solidarity becomes associated with the social will to respect patient autonomy. The importance of respect for patient autonomy is not questioned any more. Two years later in 2014, the CCNE report on the public debate about the end of life makes a similar use of the notion of ‗accompagnement' [54] and discusses the same association between autonomy and solidarity. It argues in favour of a 'véritable accompagnement humain' aiming to offer both care and cure, and to address the fear of abandonment, pain and social inequalities in access to care. Above all, this ‗accompagnement' consists in listening to patients' wishes, including their wish to stop treatment. Once again, the respect for patient autonomy is associated with the concern to guarantee social solidarity in the last stage of life.

As a result of further debates and another parliamentary report in 2015 [START_REF]Commission des affaires sociales sur la proposition de loi créant de nouveaux droits en faveur des malades et des personnes en fin de vie[END_REF], a new law on end of life issues came into force early in 2016. The ‗law creating new rights in favour of patients and persons at the end of life' recognises the right to continuous deep sedation and grants binding value to advance directives [START_REF]du 2 février 2016 créant de nouveaux droits en faveur des malades et des personnes en fin de vie[END_REF]. A closer analysis of this law shows, however, that although respect for autonomy is now considered an important value, its implementation is not straightforward. The same paragraph (L.1111-11 Public Health Code) that states that advance directives are binding for the physician mentions their possibility to challenge such a directive if it appears ‗clearly inappropriate' with regard to the medical situation of the patient. If a physician refuses the implementation of an advance directive, this decision is reexamined in a so called ‗collegial procedure' that is the treating physician has to consult other physicians. Other than in e.g. Germany or England, the physician is not hold to discuss the advance directive with the patient's family and close persons in order to establish the presumed patient wish. As Thouvenin points out, the decision to apply or not an advance directive remains a medical decision. According to French law, only physicians seem to be able to validate the authenticity or appropriateness of a previously expressed patient wish [START_REF] Thouvenin | Les droits de la personne reconnus par la nouvelle loi? Conference ‗La nouvelle loi sur la fin de vie: 10 ans de débat[END_REF]. Although French law increasingly improved the right of competent patients to make their own decisions, this is not the case for patients that are not able to express their will anymore, even if they have written an advanced directive.

Our analysis of 25 years of French end-of-life debate shows that although patient autonomy has gradually been established as an important value, it is still not easily implemented in the French context. However, the situation has not remained the same in the course of the debate, a way to combine autonomy and solidarity has been found that makes it possible to argue in favour of the respect of patient autonomy. Today, in France, those who advocate respect for patient autonomy are sometimes doing so for the sake of individual self-determination. Such respect is also justified on the basis of a conception of autonomy that is conceived as a shared collective value. In this perspective, the respect of patient wishes is seen as a leading principle in end-of-life care, not because of a rights-based individualistic conception, but because of the social duty to address the needs of dying patients. It is thus on the basis of social solidarity that the respect for patient autonomy has become legitimate in end-of-life care. As we will see in the following section, the support of terminally ill patients expresses this new combination between solidarity and autonomy. In this section, we will also examine the limits of patient self-determination and finally, we will develop our reflection on the implications of the attempt to bring together autonomy and solidarity, in order to define ‗good' end-of-life care.

Scope and limits of associating autonomy with solidarity

From the 1980s, the French debate on end-of-life was intense and heated. Gradually, this debate became more nuanced and its focus shifted from the right-to-die to more practical questions about ‗good' end-of-life care. As a response to ‗the painful ordeal' [START_REF]Fin de vie, arrêt de vie, euthanasie. Avis[END_REF] caused by futile treatment at the end of life, palliative care was integrated into hospital settings. As mentioned, in the first instance, the term ‗accompagnement' was strongly associated with palliative care and the support of the dying person surrounded not only by professionals, but also their loved ones. In a first phase, ‗accompagnement' implied respect for the patient as a person. However, it did not refer to the notion of autonomy. Patients had no right to decide about their end-of-life care. In retrospect, this social and legal pattern may be considered as a paternalistic approach.

In this first phase, the term autonomy was used to defend the right to ‗reclaim one's own death' [START_REF]Fin de vie, arrêt de vie, euthanasie. Avis[END_REF], a request considered as socially inacceptable in the documents we have presented.

Hence, autonomy could not be employed on its own as a principle to justify respect for patient wishes. Rather, the request to choose one's own death could only be taken into account if solidarity was put forward as leading moral values in end-of-life care. The CCNE report of 2000 emphasised society's duty to show solidarity with the suffering person when it argued for ‗euthanasia'; the right to choose the moment of one's death under ‗exceptional circumstances' [START_REF]Fin de vie, arrêt de vie, euthanasie. Avis[END_REF]. By referring to solidarity, a widely accepted value in French society and health care, this 2000 report intended to find an ethical justification for the highly controversial act of ‗euthanasia', based on a patient's wish. It however remained an isolated view.

From 2005, in the aftermath of the Humbert case, ‗accompagnement' was increasingly presented as an important part of medical practice, particularly where active treatment was foregone. ‗Accompagnement' was no longer exclusively linked to the provision of care for dying patients but also applied to patients who were not in the last stage of their life but had refused treatment. Henceforth, ‗accompagnement' represented respect for patient wishes, beliefs and values: from then on, physicians were expected to provide continuous support of patients even if they refuse further treatment. The term ‗accompagnement' began to embrace more than just palliative care, and was extended to care in general, whether it was medical, spiritual or social. In 2009, the National Institute for Prevention and Health Care Education (NPES) defined ‗accompagnement' as the ‗human' capacity to listen to and engage with the patient, and to show consideration for them. Increasingly, the patient became the centre of attention as a person with their own beliefs and values [START_REF]Patients atteints de maladie grave ou en fin de vie -Soins palliatifs et accompagnement[END_REF]. This vision of ‗accompagnement' strengthened the position of the patient at the end-of-life only up to a certain extent. It expresses an ethical concern about professional attitudes towards dying patients rather than it actually focuses on patient self-determination.

From 2012, the debate focused on the question as to whether patient wishes should be challenged at all. In this context, the support of patients was perceived as part of a broader social commitment not to abandon the dying person, while respecting their wishes, rather than submitting them to paternalistic medicine. ‗Accompagnement' was understood as a way of expressing solidarity, both at an individual and a social level.

The term ‗accompagnement' is worth commenting upon: it is not an ethical or philosophical notion, but a term used in ordinary language and daily life, and easily understood by everyone. It has a positive meaning and describes a way of ‗being with others', a willingness to ‗stand by each other' [START_REF] Jaeggi | Solidarity in Health and Social Care in Europe[END_REF]. A ‗companion' designates a person you can count on, who respects you, shares your interests and does not try to dominate you. It is widely used to describe ‗good' professional practice, not only in medical contexts, but also in the broader context of social community care and education. As such, the term is used to emphasise both respect for another person's wishes, beliefs, and needs, and the support provided by being ‗at their side'.

In the strongly polarised French end-of-life debate, the use of the term ‗accompagnement' is not incidental. Facilitated by the ordinariness of the term in French language and its broad acceptance in French society, it allows its users to describe a viable combination of autonomy and solidarity. It cannot be considered as a theoretical justification of this combination, but as an effective rhetorical tool to convey it in the public debate, both at an ethical and legal level.

On the one hand, ‗accompagnement' allows acceptance of patient autonomy within some limits, as we will see below. In legal terms, since February 2016, this means that a patient who is able to express their will is entitled to receive every necessary care to alleviate their pain. Patients may also refuse medical treatment, including nutrition and hydration. Finally, the law sets up a procedure for continuous deep sedation when the suffering of the patient is considered as unbearable and the patient is in their last stage of life. On the other hand, the use of the word ‗accompagnement' is also a way to acknowledge the role of medicine and society as a whole: patients are those who are ‗accompanied' in the sense of supported; and medicine and society are their ‗companions' who provide the support. They are accounted responsible for creating the necessary conditions for ‗good' end of life care [54]. Therefore, both medicine and society play an important role in deciding what constitutes a ‗good' endof-life. The term ‗accompagnement' finally allows solidarity and autonomy to combine. Even if, in practice, the focus on patient support may lead to shared decision-making, the question at stake is not to reach a shared decision process or some kind of ‗mutuality' in the patientphysician relationship [START_REF] Smith | Physician and patient: Respect for mutuality[END_REF].

If we understand communitarianism as a perspective that places the needs of society over those of the patient, France does not opt for a communitarian approach to end-of-life care when combining solidarity with autonomy. Neither does France opt for a liberal approach that privileges individual autonomy or an intermediary solution such as the ‗responsive communitarianism' defined by Etzioni, according to which autonomy and solidarity are part of a conflict that may never be fully eliminated, but can be worked out on a procedural basis [START_REF] Etzioni | On a communitarian approach to bioethics[END_REF]. A different pattern is set by the recent shift of the French debate about end-of-life care: autonomy is not respected because individual freedom is considered as the prevalent (if not unique) moral and political value, but rather because society as a whole grants importance to individual freedom and wants to care for the dying in the name of solidarity. Here, solidarity is not opposed to autonomy: it rather combines with it, in the sense that autonomy is granted importance to the same extent as it is recognised as a value of the society as a whole.

We argue that this combination between solidarity and autonomy in the context of the French end-of-life debate is made possible by a conception of the individual as part of the whole, or to put it in Ricoeur's words, as able to think of ‗oneself as another' [START_REF] Ricoeur | Soi-même comme un autre[END_REF]. This conception develops a social (as opposed to an atomistic) understanding of human life and personal identity [START_REF] Jaeggi | Solidarity in Health and Social Care in Europe[END_REF]. Thinking of oneself as existing within the limits of society thus appears as the condition for the recognition of individual freedom. This combination also relates to a conception of solidarity understood as the expression of a shared social duty towards dying and vulnerable patients. This shared social duty is not to be understood in the sense of Rousseau's general will, but as the expression of a social duty to support each other, namely to support the weaker members of society. This conception also entails that granting patient autonomy a central position does not entail the moral legitimacy of every request to die. The increased focus on patient autonomy in the French society has its limits when speaking of autonomy as self-determination. For example, the most recent law of 2016 does not allow euthanasia, even in exceptional cases. Patients may make their own decisions, yet they are not allowed to transgress the values of a society that is not ready to define a legal framework for ‗active' forms of assisted dying.

Thanks to the social conception of the individual, the search for a balance is between ‗individual freedom' and the ‗common interest' is made possible [54]. Nonetheless, the use of the term ‗accompagnement' should not blind us to the existence of divergent views on what is ‗good' end-of-life care. These differences cannot be ignored despite the attempt to harmonise autonomy and solidarity, as described in this paper. As we have stressed, there is still strong disagreement as to how much autonomy should be granted to a patient at the end of life both when patients are able to express their will and when they are not and have left advanced directives.

Conclusion

Our paper shows how the association of the ideas of solidarity and autonomy led to the social acceptance of the latter in the French context. Whereas solidarity is a determining value in French society, least within the French health care system, respect for patient autonomy has long been considered a foreign concept, deriving from the liberal Anglo-American tradition.

At first, respect for patient autonomy was associated with the right to a self-determined death, a request that seemed incompatible with French values, which are based on a model of social cohesion and emphasise the protection of vulnerable members of society such as dying persons. Patient autonomy was only gradually recognised as an important value in the French end-of-life debate, yet to this day its practical implementation is not evident and its scope remains restricted. It was the redefinition of ‗accompagnement', a notion originally reserved to describe palliative care, which triggered a shift in the debate. This shift happened in 2012 when ‗accompagnement' was employed to justify the right to terminal sedation at a patient's request. The respect for patient wishes was associated with some kind of social duty towards the dying person and appeared now as consistent with the general will of society as a whole. It is precisely this association between autonomy and solidarity that allows the leading moral principle of solidarity in confining the limits of individual self-determination.

The case of the French end-of-life debate illustrates clearly that solidarity and autonomy are not per se incompatible but can inform each other's meaning and understanding in a particular context. In the French context, this association leads to a definition of autonomy that is promoted as a common social value, on the one hand, and limited by social values such the protection of the dying person, on the other hand. In this definition, solidarity and autonomy become two compatible values, although this compatibility is limited. We see this as an important contribution to the bioethical debate inclined to emphasise the incompatibility of Anglo-American and Continental European values.

We would like to point out that the French end-of-life debate mainly focuses on cases that take place in a hospital setting.

funded by the Wellcome Trust (106152/Z/14/7). We are grateful to the participants who contributed to discussion of the paper and to Susan Barrington for reviewing the text. We would particularly like to thank Ruud ter Meulen for his detailed comments on earlier drafts of this paper.

Compliance with Ethical Standards

Conflict of interest: none Research involving Human Participants and/or Animals: N/A Informed consent: N/A