Martina Požar

Aurélien Perera

On the micro-heterogeneous structure of neat and aqueous propylamine mixtures: a computer simulation study

The micro-heterogeneous structure of neat and aqueous propylamine is examined through computer simulations. Neat propylamine is found to have a pre-peak in the nitrogen-nitrogen structure factor, due to the presence of branched chain-like aminogen clusters. Aqueous propylamine mixtures are found to be micro-segregated at all amine concentrations. Both the waterwater and the amine nitrogen-nitrogen structure factors show the caracteristic domain pre-peaks in their respective moderate to high contents. The amine cluster pre-peak, still visible at high amine content, disappears into the domain pre-peak at lower amine contents. Interestingly, water domains forms linears clusters for water concentrations below equimolar. We discuss the specificity the amine brings to the nature of the water clustering as compared with other type of solutes. In particular, we find that the Kirkwood-Buff integrals are quasi-ideal in the amine mole fraction range 0.3 < x < 1, which we interpret as being consistent with the linear water clusters observed in this range, and which act as individual supra-molecular entities. We conjecture that such cluster shapes are consistent with the existence of a lower critical solution temperature for this system as well as other aqueous amines.

A C C E P T E D M A N U S C R I P T 1 Introduction

Amines play important role in industrial [1,2,3] and pharmacological [4,5] applications, but also in biological processes [6,7,8,9]. They bear an interesting resemblance with mono-ols in that they form hydrogen bonds through the lone pairs of the nitrogen atom. Since alcohols form micro-heterogeneous mixtures with water [10], one equally expects amines to behave similarly. However, the NH group of amines has a 2 donor -1 acceptor, instead of the 1 donor -1 acceptor structure of OH hydroxyl group of linear alcohols. How does this difference affects the micro-structure of neat amines and aqueous amine mixtures? For example, it is well known that linear alcohols form chain-like cluster structures, which produce a pre-peak in the oxygen-oxygen structure factor and the total scattered intensity as seen through neutron or Xray diffraction experiments [11,12]. The existence of two donor sites for amines would favour branched chains. How this particularity could affect amines, as compared to linear mono-ols? Lower amines such as methylamine and ethylamine are gases under ambient conditions, while methanol and ethanol are liquid. This fact indicates that, despite their double hydrogen bonding structure, amines have less hydrogen bonding capabilities than the corresponding mono-ols. In order to appreciate this difference, it is instructive to look at the classical force field representation of the hydrogen bonding through their Coulomb contributions as partial charges on the oxygen, nitrogen and hydrogen atoms. The Optimized Potential for Liquid Simulation (OPLS) [13] force field attributes for propylamine the valence z N = -0.9 to the nitrogen atom and valence z H = +0.360 to the hydrogen atom. Similarly, it attributes for 1propanol the valence z O = -0.7 to the oxygen atom and the valence z H = +0.435. Both sets of values are about the same order of magnitude. Therefore, it seems reasonable to consider that it is the topology of the amidogen NH 2 group of the amine molecules which does not allow as much hydrogen bonding as the hydroxyl OH group of the alcohol molecules. In particular, the proximity of the two hydrogen atoms next the nitrogen atom may hinder efficient hydrogen bonding. This fact may have its importance in the cluster formation and micro-heterogeneous domain formation under mixing conditions. For example, it is experimentally known that aqueous amine mixtures tend to have a lower critical solution temperature (LCST) [14]. This is in variance with aqueous mixtures of small alcohols, which generally tend to have an upper critical solution temperature under ambient pressure conditions, such as aqueous 1butanol (at 397.9K [15]) and 2butanol (at 390.35K [16]), for example. It is tempting to associate this difference between the two types of mixtures to the underlying topological properties of the two types of solute molecules. For example, in terms of the degree of hydrogen bonding, alcohols may tend to form a more coherently bonded liquid than amines, under ambient conditions, which could explain the temperature dependance of the way these liquids mix with wa-

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ter. In this context, it is interesting to ask how this difference would affect the type of micro-heterogeneity these mixtures have. Amines have not been studied by computer simulation as much as alcohols, as can be seen by the scarcely available force fields [17], other than the usual Gromos [18,19] and OPLS [20,21] transferable force fields. Kusalik et al. [22] have studied methylamine and aqueous methylamine. Lachet et al. [17] have studied a large variety of alkanolamines and their aqueous mixtures, and have proposed a new force field in order to obtain better excess enthalpies.

The principal objective of this paper is to use our previous studies about microheterogeneity to explore for the first time the micro-heterogeneous structure of both neat and aqueous propylamine. This study is a continuation of previous studies where we have shown that the structure of the solute molecule greatly affects the way water segregated domain forms. For example, in aqueous alcohols, water tends to form bulky domains [23,24]. In aqueous DMSO, water forms chain-like cluster domains [25]. In both cases, the existence of such segregated domains has two distinct type of impact on the structural and thermodynamical properties of such mixtures. Firstly, a domain pre-peak is found in the oxygenoxygen structure factor S OO (k) at a k-vector intermediate betwen k = 0 and the main peak about k = 2π/σ w ≈ 2Å -1 , the latter which corresponds to the the diameter of the water molecule σ w ≈ 3.1Å. The exact position of this peak, as well as its height, depends on the bulkiness of the segregated water domains. Secondly, the concentration fluctuations depend on the nature of the domains, and tend to be rather high for domain that are fuzzy (such as in tbutanol-water) or with large polydispersity (such as in benzene-ethanol), and small for domains with well stabilized shapes (such as aqueous-DMSO) [26]. Concentration fluctuations, defined as C i j =< N i N j > -< N i >< N j >, where N i is the number of molecules of species i in a given volume V , are related to the structure factors S i j (k = 0) through the relation [START_REF] Hansen | Theory of Simple Liquids[END_REF]

S i j (k = 0) = < N i N j > -< N i >< N j > < N i >< N j > (1)
In a recent work [START_REF] Požar | [END_REF], we have argued that segregated water domains were made of groups of smaller water clusters, the latter which were the elementary entity behind micro-segregation. This way of looking at micro-segregation opens new perspectives with respect to general physical chemistry, mainly for a new interpretation of phenomena such as, for example, the hydrophobic effect [START_REF] Tanford | The hydrophobic effect: formation of micelles and biological membranes[END_REF][START_REF] Kauzmann | [END_REF]31,32], as well as the role of water in the biophysical context [33,34]. The way water forms clusters and the way these clusters group themselves into larger domains or not, seems to depend very strongly on the nature of the solute [26]. For these reasons, it is interesting to explore particular solutes, in order to understand

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the common mechanism behind the behaviour of water. We have chosen propylamine since it is miscible with water at all proportions, and lower alkylamines are less miscible.

In the present paper, we will adopt the same type of approach that we have considered in our previous ones, namely with respect to force fields. While it is important to represent force fields properly in order to reproduce best target physico-chemical properties, we adopt the view that these considerations do not affect qualitatively the micro-segregation property of corresponding aqueous mixtures. In other words, while peculiar details of micro-heterogeneity, such as the pre-peak height and position, for example, might be as sensitive to force field details as other physical properties such as excess enthalpy or density, for example, its existence is essentially robust to such details. This approach has been particularly successful in allowing to predict the correct experimental Kirkwood-Buff integrals (KBI), despite strong differences in the short range correlations corresponding to different force fields, for example in the case of aqueous tbutanol [23] and aqueous acetone [35]. This is an important consideration since the KBI are expressed in terms of volumetric quantities as well as chemical potential derivatives, which are all sensitive to force field details. Since the KBI are representative of the nature of concentration fluctuations, these findings imply an interesting universality relationship between the robustness local molecular organisation, such as clustering or micro-segregation, and force field details.

Model, Simulation and Theoretical details

All simulations were performed with the program package Gromacs [36]. The forcefield Gromos53a6 [18] was used to model propylamine, while SPC/e [START_REF] Berendsen | Intermolecular Forces[END_REF] was chosen for water. Apart from neat propylamine, we have simulated the propylamine-water mixture over a range of concentrations, typically for propylamine mole fractions of 0.2, 0.5 and 0.8. The box of neat propylamine contained 2048 particles, corresponding to the box length of 64.7 Å. As for the propylaminewater mixture, system sizes of both N = 2048 and N = 16000 were considered, yielding an average box size of 54.6 Å and 108.4 Å, respectively. The force field for 1propanol, used for comparison purpose, was taken from the OPLS series [13] and a system of N=2048 molecules was simulated.

The systems were simulated in the isobaric-isothermal (constant NpT) ensemble, at the temperature of T = 300K and pressure p = 1 bar. Those conditions were achieved with the Nose-Hoover thermostat [START_REF] Nose | [END_REF]39] and Parrinello-Rahman barostat [40]. We followed the same procedure for every simulation. Packmol [41] was used to obtain the initial configurations of the systems from the pdb files of each molecule. After energy minimization, the systems were equilibrated in the NVT and then NpT ensemble, for a total of 1 ns. The following production runs lasted 4 ns, in order to sample at least 2000 configurations for calculating site-site correlation functions g a i b j (r), where a i , b j represent any two atomic sites on the molecules and i, j correspond to the species index.

On top of site-site correlation functions, we calculated the site-site structure factors S(k), defined as [START_REF] Hansen | Theory of Simple Liquids[END_REF]:

S a i b j (k) = S a i b j + ρ √ x i x j d r[g a i b j (r) -1]exp(i k r) ( 2
)
where ρ is the number density and x i the mole fraction of species i. The values we report here are obtained by direct Fourier transformation of the correlation functions g a i b j (r) by standard numerical methods [START_REF] Brigham | The Fast Fourier Transform[END_REF]. As for displaying the structure factors, we follow the same convention as in our previous works and replace δ a i b j with 1 in the figures.

Cluster distribution probabilities are calculated within the Gromacs program. The Kirkwood-Buff integrals [START_REF] Kirkwood | [END_REF], mentioned in the previous section, are defined as:

G i j = d r[g a i b j (r) -1] (3)
where g a i b j (r) is the site-site correlation function. Since these integrals can be related to macroscopic thermodynamic quantities, they depend only on the species index, and not on the atomic ones [START_REF] Hansen | Theory of Simple Liquids[END_REF]. As explained in our previous works [35,44], these integrals cannot be evaluated directly from correlation functions obtained in the simulation, since these latter are affected at long range by the concentration fluctuations inside the simulation box, and do not tend to the expected asymptote, as was shown by Lebowitz and Percus [45]. We have developed a procedure to account for this problem [44,26].

The KBI are defined from the relations derived from the KB theory [START_REF] Kirkwood | [END_REF]46,47] G

i j = k B T κ T -Vi Vj V D (1 -δ i j ) + G 12 + 1 x i Vj D -V δ i j (4)
where κ T is the isothermal compressibility (k B is Boltzmann constant and T the temperature), Vi is the partial molar volume of species i, V the total volume and D is related to the concentration fluctuations through the expression [START_REF] Kirkwood | [END_REF]46,47]

D = x i ∂ β µ i ∂ x i T P (5)
where µ i is the chemical potential of species i (β = 1/kT is the Boltzmann factor).

In practice for dense liquids, the compressibility term is small compared to the others and can be ignored. In addition, we neglect the usually small variations

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with mole fraction of of the partial molar volumes -which amounts to neglect ∂V excess /∂ x i (the excess volume V excess is usually at least one order of magnitude smaller than the volumes [48]), and replace these by the volumes of their respective neat systems. This way, the KBI defined in Eq.( 4) can be simply related only to the volumes and mole fractions, and the D term needs to be evaluated indirectly. If we write the chemical potention into its usual three different contributions (reference, ideal and excess parts):

µ i = µ (0) i + k B T ln(ρx i ) + µ excess i
, then one gets [47,46]

D = 1 + x i ∂ β µ excess i ∂ x i T P (6)
Under this form, we see that if the excess part becomes independant of the solute concentration, then D = 1 is reduced solely to its ideal contribution from the chemical potential. One may ask how the excess part may become independant of the solute concentration. By analogy with phase coexistence of a binary mixture, where the chemical potential is the same across the separating interface (by one of the necessary conditions for phase coexistence), then micro-segregation may be considered as a smaller scale version, or rather a local version of phase coexistence. In other words, the condition D ≈ 1 is consistent with micro-segregation. It does not necessarily imply that that the mixture is ideal, but that concentration fluctuations are negligible despite the micro-heterogeneous configuration. Of course, this condition is not achieved for any micro-heterogeneous mixture, such as in the case of aqueous-alcohol mixtures, for example [47]. We have shown [25] that aqueous-DMSO mixtures behaved as quasi-ideal, due in particular to the fact that almost all water molecules were clustered into small linear aggregates, which acted as supra-molecular entities in order to enforce a quasi-ideality of this particular mixture, as far as the KBI were concerned.

3 Results

Neat propylamine

The left side of Fig. 1 shows a snapshot of the N=2048 neat propylamine system, where only the nitrogen and hydrogen atoms are show in filled colored balls, while the methyl united atoms are shown as semi-transparent balls. This way, one can clearly see a number of chain-like patterns formed by the bonding sites. The right side shows a snapshot of the N=2048 neat 1propanol system, where the oxygen atoms are shown in red and the hydrogen in white, with the same convention for the methyl united atoms. This snapshot equally shows visual evidence for chainlike patterns formed by the hydroxyl groups. There is however a big difference between the chain patterns between the two snapshots: those of the propylamine

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system show considerable branching and polydispersity, due to the double hydrogens on the nitrogen site. Another way to represent the difference between the branched and neat chains in the two systems, is to calculate the cluster distributions formed by the nitrogen and oxygen atoms. This is shown in Fig. 2. The cluster distribution of the oxygen atoms of the 1propanol system shows a clear peak around cluster size 4-5, just like that found for methanol [50,51], ethanol [START_REF] Požar | [END_REF] and tbutanol [50,51]. Conversely, the cluster distribution of the nitrogen sites of propylamine shows a very weak shoulder about the same cluster size. However, the monomer probability is higher for propylamine than 1propanol. These results are a direct consequence of the visual information of Fig. 1: simple chains produce a visible count, while branched chains tend to blur the distribution of aggregated atoms and produce a weak broadened feature instead.

Fig. 3a shows the N-N correlations in blue and the N-H correlations in red. The thin and high N-N first peak is typical of the hydrogen bonding between the nitrogen sites, intermediated by the hydrogen sites, just like for water and alcohols [23]. However, unlike water and alcohols, the N-H first correlations are lower than the N-N correlations and show a split two peaks pattern. This is due to the direct N-H bonding for the peak at the smaller r value and the indirect bonding positioned at the same distance as the N-N bonding distance through the second hydrogen. These correlations are equally distributed among the two possibilities, which is why they are about twice smaller than the N-N correlations. This observation directly supports the conjectures of the relation between the topology of the solute molecule in relation to its bonding ability. The inset of Fig. 3a shows the correlations between the same methyl sites. These correlations are about the same magnitude as the N-H ones, and those between the methyl atom closest to the nitrogen atom have the smallest first peak, indicating a least probable contact between these united atoms.

Fig. 3b shows particular site-site structure factors, as compared to the pure 1propanol structure factors [49] in the inset. The N-N structure factor shows a prominent pre-peak at k ≈ 0.65Å -1 , which corresponds to a structure of approximately 10Å, which is representative of the nitrogen trimer cluster. This corresponds probably to the basic nitrogen aggregates that form the base of the branched chain-like clusters seen in Fig. 1. We note that the N-H structure factor equally reveals this cluster pre-peak, almost superimposed to the N-N one. The second peak is centered about k ≈ 3Å -1 , which corresponds to the Hbonding distance of r HB = 2Å. In contrast, the methyl sites show an ordinary Lennard-Jones type structure factor, with a main peak centered at k ≈ 1.4Å -1 which corresponds to the mean diameter of the methyl site. The oxygen-oxygen (O-O) and oxygenhydrogen (O-H) 1propanol structure factors in the inset have a higher pre-peak than the N-N and N-H structure factors of propylamine, which indicates that, for

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the same number and same topology of the methyl sites, the hydrogen bonding difference between straight and branched chains tends to weaken the pre-peak of the latter type of chains. This fact directly supports the arguments developed in the Introduction.

The study of the correlations, both in direct and reciprocal space reveals the Hbonded cluster structure, very much like in alcohols [50,51], however with the differences induced by the 2 donor hydrogen sites.

Aqueous propylamine

Altough the snapshots are reported for N=2048, all the reported correlations are for the N=16000 systems. This allows better accuracy of the pre-peak features reported below. We studied particularly the propylamine mole fractions x = 0.1, 0.2, 0.5 and 0.8.

Snapshots

Fig. 4 shows three snapshots of the aqueous propylamine mixtures,taken at the amine mole fractions of x = 0.2, 0.5 and 0.8. The segregated domain structure is quite obvious in the first two snapshots, with bulky water domains for x = 0.2 and more linear clusters shaped domains for the equimolar case. These water domains stay very much linear at the highest amine concentration of 0.8, with few dimers and monomers, as seen by transparency in the last snapshot.

Cluster distributions

Fig. 5a shows the cluster distribution for propylamine sites (nitrogen in the main panel and the last methyl M3 site in the inset) and Fig. 5b shows that for the oxygens of water. Both panels show the distributions for 3 mole fractions of propylamine, x=0.2 in red, x=0.5 in green and x=0.8 in blue. The black curves are for the respective neat systems.

The distribution of large nitrogen site clusters loses its weak shoulder as soon as water is present, and this probability becomes smaller, which indicate a lessened clustering of propylamine with increasing water content. The monomer probability follows the expected rule that their number is larger with smaller propylamine content. The distribution of clusters of the methyl group shows more clustering at small propylamine content x=0.2 , which indicates that the oily tails may aggregate to shy away from water and the charged head groups, much like for micelles, but at a smaller scale. Conversely, their distribution tends to remain unchanged at higher propylamine content, indicating that they behave much like in pure propylamine.

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The cluster distribution for the water oxygens shows a trivial trend, with the clustering increased with lesser water content -which is compatible with microheterogeneity-except for the equimolar mixture x=0.5, where the larger cluster size above 5 seem to become prominent than in any other concentrations. This is mostly due to the presence of a large number of chain-like clusters (as seen in the middle snapshot in Fig. 4). The fact that the smaller cluster probability of this particular concentration is slightly smaller than the others, indicates that this depletion of this population is compensated by the presence of larger clusters. These differences are however very small, probably indicating a branched structure in the water chains. Indeed, if the water clusters were straight chains, one would probably observe a typical peak such that seen in Fig. 2 for neat 1propanol. Branching of chains tends to broaden the distribution.

Site-site correlation functions

Fig. 6 shows the most informative correlation functions of the aqueous propylamine mixture, for the same typical amine concentrations as in Fig. 4. The leftmost picture shows the water oxygen-oxygen correlations. It is seen that the first and second neighbour correlations increase with decreasing water content (as observed in the inset which shows a zoom on the pre-peaks). However, a shallow minimum appears beyond the third neighbour correlation, which corresponds to the minimum of the cluster domain correlations, more visible for x = 0.8, and in agreement with the linear clusters seen in the right snapshot in Fig. 4. The shallow minimum corresponds to the minimum of cluster-cluster correlations, which superimpose to the atom-atom correlations. This feature demonstrates the existence of supramolecular water aggregates.

The central panel shows that the water oxygen and amine nitrogen correlations are less important than the water-water correlations, although these correlations tend to show a similar increase with water content decrease. We conclude that that water interacts and form hydrogen bonds preferentially with the surrounding amines when these are in majority. This could explain the presence of water monomer, dimer and small clusters. However, these correlations are seen to be depleted beyond 2 neighbours, indicating the short ranged correlations between antagonist bonding species.

Finally, the rightmost panel shows that the N-N correlations for x = 0.1 are the smallest of all at first peak level, and that these first peak correlations increase with amine content increase -which is exactly opposite of the behaviour of water. This shows the dramatic difference between Hbonding pattern of water and amine. It is very similar to that we have previously reported in alcohols [START_REF] Požar | [END_REF]. We equally observe that the N-N correlations are very small and depleted at contact for x = 0.1 andx = 0.2, which shows that the amines tend to Hbond with water rather than

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with themselves. Incidently, for the x = 0.2 case, we have compared the correlations of the N=16000 system reported here (in purple) with those of the N=2048 system (in red). It is see that there is almost no influence of the system size as far as short range correlationas are concerned.

Structure factors

The structure factors of the water oxygen-oxygen correlation, reported in Fig. 7 (left panel) show the typical domain pre-peak correlations that we have previously reported for many other aqueous mixtures. The pre-peak is seen to be more important at high water content for x = 0.2 (water mole fraction 0.8). This is absent for pure water (thin black line). This peak corresponds to the bulky and percolating water domain see in the right panel of Fig. 4. As these domains thin out and become linear water clusters, this pre-peak diminishes in proportion. It is interesting that the pure water outer peak of the well known split peak feature [52] -which represents the oxygen-oxygen contact peak, vanishes for any amine content, and only the inner Hbond peak at k ≈ 3Å -1 (corresponding to r HB ≈ 2Å) survives, although it decreases with amine content increase. This tends to indicate that the water molecules are less Hbonded at high amine content than at low one, which appears inconsistent with the high first peak of the water correlations in Fig. 6 left panel. This apparent discrepancy demonstrates that the increase of the first peak of the g OwOw (r) functions are not only related to direct Hbonding (such as in pure water), but that they also include broader cluster correlations, as clearly shown by the apparent broadening of the first peak in the inset of Fig. 6 left panel.

The middle panel shown O-N cross structure factors, which are seen to have both positive and negative pre-peak at the place where OO have only a positive domain pre-peak. This type of anti-pre-peak is typical of domain segregation, and has beed repeatedly reported in the room temperature ionic liquid literature [53,54,55]. This is a very important information in the present context, since it shows that only the case x = 0.2 shows the anti-pre-peak, when the cross structure factors for x = 0.5 and 0.8 show positive pre-peaks. This allows us to distinguish between the case where water forms bulky domains (see Fig. 4 left panel), which is more synonymous of micro-segregation, from the case where water forms rather linear clusters (as in Fig. 4, middle and right panels). This distinction is important, since we argue that water tends to naturally form linear supra-molecules in mixing conditions, and that water segregated domains are often aggregates of such supramolecular linear water clusters [56].

Finally, the rightmost panel shows the N-N structure factors. One sees that, at hight amine content, the pure amine cluster pre-peak (in thin black line -also discussed in Fig. 3 right panel) tends to vanish progressively as the amine content di-

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minishes, while the domain pre-peak emerges (as see at x = 0.2 and x = 0.1). This latter case corresponds to the bi-continuous segregation of water and propylamine -as seen in snapshot of Fig. 4 left panel. The disappearance of the neat amine cluster pre-peak means that propylamine in the domain is more likely Hbonded to water, forming some sort of nitrogen atom interface between the water domains and the alkyl groups.

The influence of the system size dependence is more apparent for the structure factors than for the correlation functions, as seen from the data reported for x = 0.2 (purple for N=16000 and red for N=2048). This difference, even though small, shows that the domain formation is influenced by the system size. However, this difference is not as important as in the case of other mixtures, such as aqueous TBA [23], aqueous acetone [35] or ethanol-benzene [57]. This is attributed to the differences in the micro-heterogeneity and clustering of water, namely the linear clusters found here as opposed to the bulky clusters found in the latter mixtures. Indeed, the distribution of bulky clusters are more likely to be influenced by system size. We observe that the differences in the present context are more important for small x = 0.2 value, for which bulkier clusters are seen (Fig. 4 left panel).

Kirkwood-Buff integrals

Since these mixtures look strongly non-ideal, one might expect high values of the KBI. But Fig. 8 shows that the KBI computed from the simulation results are quite small, which is very surprising in view of what is seen for other aqueous mixtures, where the KBI are rather large. We have shown in many cases [58,59,23,35] that the amplitude of the KBI reflect the effective concentration fluctuations. We have plotted the ideal KBI in dashed lines, and Fig. 8 shows that the KBI are nearly ideal in the range 0.3 < x < 1. In fact, this is very consistent with the finding reported above. In previous studies, we have underlined that the presence of linear water cluster (supra-molecular water) often leads to small KBI, which means small concentration fluctuations. Indeed, if we try to calculate the D-function from the KBI obtained from the simulations, we obtain the curve shown in the inset, which is equal to 1 in the range 0.5 < x < 1. From Eq.( 5), this latter information implies that the derivative of the excess chemical potential is zero, which indicates that the chemical potential become independant of the concentration. We interpret this as consistent with water forming tightly bonded supra-molecular entities, which interacts with the rest of the system weakly. This is similar to what we found in benzene-alkane mixtures [57], where D ≈ 1 was equally found, despite strong molecular interactions. The condition D = 1 does not mean that there are no interactions, but that the system is homogeneous in terms of clustered or supra-molecular entities. Water specific interactions are strongest in the range

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3, as seen from the non-ideal KBI. It is seen that it is the amine-amine KBI that the most non-ideal, showing that propylamine clustering at small amine content is not trivial. Since D(x) represent the concentration fluctuation term, we see that these are maximal around x ≈ 0.15, close to the case x = 0.2 that we have explicitly reported as showing bulky clusters.

4 Discussion: UCST versus LCST

As stated in the Introduction, the existence of UCST for aqueous alcohols as opposed to LCST for aqueous amines, can be speculatively understood in terms of the types of water aggregates formed in these different mixtures, namely bulky versus linear aggregates. This is evidently induced by the different type of hydrogen bonding of these respective solute molecules. The main line of argument is that bulky water aggregates have most of their hydrogen bonding sites selfsaturated by water molecules, hence bind less with surrounding solutes than linear water aggregates, which have more open bonding sites to solutes. As a consequence, bulky water aggregates are likely to grow by coalescing, and lead to phase separation under mixing unstability conditions. Such conditions are likely to happen at lower temperatures than higher ones for the simple reason that thermal agitation is likely to increase the disorder of the aggregates rather their coalescence. Hence, aqueous alcohol mixtures with bulky water aggregate domains are likely to have a UCST [15,16]. Conversely, the explanation for the existence of a LCST in micro-segregated mixtures seems to be more involved. With that respect, we would like to point out that the currently accepted explanations for the existence of LCST and UCST are essentially related to the seminal paper from Walker and Vause (WV) [60]. While the existence of UCST can be quite simply attributed to mixing under thermal agitation at higher temperature, the WV approach explains remixing at a lower temperature below the LCST as the result of a preferential directional attraction between the two species. This is fully consistent with the hydrogen bond and the experimental fact that LCST exist only in Hbonding mixtures [60]. In this picture, remixing at lower temperature involves essentially the existence of solute-solvent dimers, which overcome the globally unfavourable solute solvent interactions. However, the VW approach does not account for the existence of microsegregation. Micro-segregation is a stronger principle than a mere solute-solvent directional association. Quite the contrary, it is a local self-segregation of each species, but maintained by cross species interactions across the local domains. Hence, one needs to revisit the WV mixing conditions by taking into account aggregation. The case of the UCST was discussed above at the beginning of the paragraph. We now discuss the case of LCST, in relation to the existence of linear

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water aggregates. In comparison with the difference in bonding between alcohols and amines, namely the lower bonding abillity of amines as discussed in Section 3.1, we hypothetize that linear water aggregates exist because of an appropriate balance between the Hbonding abilities of the solute and water. An increase in temperature will further disfavour the Hbinding ability between water and the amine, due to thermal disorder, leading to increased self-association of water and eventually demixing. Hence, the existence of linear water aggregates is an indirect signature of the nature of the associations between water and the solute, and a possible precursor for an LCST behaviour. The tentative explanation for the existence of LCST in amine aqueous mixtures with linear water aggregates, while pictorially appealing, needs to be confirmed with other cases. For example, aqueous 2-butoxyethanol mixtures have an LCST [61,62] while this solute is an alcohol. However, it has an ester group, hence it may favour water-solute interactions more than solute-solute interactions, and induce the presence of linear water aggregates at temperature below its LCST (around 320K). The computer simulations of Gupta and Patey [63,64] show that demixing consistent with the LCST, appears in the appropriate temperature range, although such simulations require very large system sizes (62000 molecules) in order for the existence of LCST to be settled. We note that the WV picture for LCST is illustrated mainly for binary alcohol mixtures with glycerol as solvent [60]. Since alcohols tend to form chain-like associated structure with their hydroxyl group, it is not excluded that the influence of chains is also an essential mechanism behind the presence of an LCST in these mixtures.

Conclusion

The study of model aqueous propylamine mixtures reveals specificities of water segregation that we have observed in several different contexes. In the range 0 < x < 0.3 we find that water forms bulky domains, similar to that we have observed in aqueous alcohols [24,23], which lead to a prominent domain pre-peak in the oxygen-oxygen structure factor. In contrast, in the range 0.3 < x < 1, water forms linear clusters, similar to what we found in water-DMSO mixtures [25], and leading to modest structure factor pre-peaks and near ideal KBI. Hence, the aqueous propylamine behaves in a composite manner, between aqueous alcohols at low solute content and aqueous DMSO at high solute content. In fact, despite high structure factor pre-peak at small solute content, this system has quite moderate KBI, which indicates that it is nearly ideal, and consequently acts as a well mixed and homogeneous system in terms of supra-molecular entities. This is an interesting system, which seems nearly ideal, despite very strong Hbonding interactions, but which tend to self-segregate each species into weakly interacting

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macro-molecular entities, and probably more the water than the amine molecules. The discussion above opens several questions about the kinetics of the water aggregation under mixing conditions. What is the exchange time constant of monomeric water molecules between the clusters entities? How does this kinetic influences the dynamical properties rather than the static properties. We do not provide answers to these questions in this work. Beyond these questions, the interpretation proposed here deserves a deeper investigation, perhaps to eventually lead to a better understanding of the well documented, but still not deeply understood phenomena such as the hydrophobic effect, and the role of water in the biophysical context.

• Fig. 1 -Snapshot of neat propylamine for system size N=2048. The nitrogen sites are shown in blue, the hydrogen sites in white and the methyl group united atom sites in semi-transparent cyan.

• Fig. 2-Cluster distribution probabillities for the nitrogen atoms of propylamine in blue and in red for the oxygen atoms of 1propanol.

• Fig. 3 • Fig. 6 -Selected site-site correlation functions of the equimolar aqueous for different propylamine mole fractions : x = 0.1 in jade, x = 0.2 in purple (red a for the N=2048 system), x = 0.5 in blue and x = 0.8 in cyan; pure water (left panel) and pure propylamine (right panel) in black . Left, middle and right panels correspond to for the oxygen-oxygen, oxygen-nitrogen and nitrogen-nitrogen correlations, respectively.

• Fig. 7 -Selected site-site structure factors corresponding to the correlation functions shown in Fig. 6 with the same color and panel codes.

• Fig. 8 -Kirkwood-Buff integrals of the aqueous-propylamine mixtures. Color code is as follows, blue for water-water, magenta for propylamine-propylamine and green for the cross KBI. Open squares are the KBI from the present simulations, full lines correspond to the D-coefficient shown in the inset (see text) and dashed lines are the ideal KBI.

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A

  C C E P T E D M A N U S C R I P T A C C E P T E D M A N U S C R I P T A C C E P T E D M A N U S C R I P T A C C E P T E D M A N U S C R I P T

•Fig. 4 -•Fig. 5 -

 45 -(a) Selected site-site correlation functions. Nitrogen-nitrogen correlations in blue, nitrogen-hydrogen in red. The inset shows selected methylmethyl correlations(see text): M1-M1 in magenta, M2-M2 in orange and M3-M3 in brown. (b) Sites-site structure factor corresponding to some of the site-site correlations shown in (a) with the same color codes. The inset shows the structure factors for neat 1-propanol[49] (O-O in blue, O-H in red and M2-M2 in orange) Snapshot of the aqueous propylamine mixtures for 3 different propylamine mole fractions: left for x = 0.2, middle for x = 0.5 and right for x = 0.8. Water molecules oxygen and hydrogen atoms are shown in red and white, respectively, propylamine molecules are shown in dark blue, except for the right panel where they are shown in semi-transparent blue. Cluster distribution probabilities versus cluster size for (a) the nitrogen sites in the left panel (last methyl site in the inset) and (b) the oxygen sites in the right panel. Red curves are for propylamine concentration x = 0.2, green for x = 0.5 and blue for x = 0.8. The black lines are for the pure systems.

Figure 2 AFigure 3 Figure 4 AFigure 5 Figure 6

 23456 Figure 2

Figure 7 A

 7 Figure 7

Acknowledgments

M. Požar thanks both the Croatian Science Foundation for financial support under the project 4514 "Multi-scale description of meso-scale domain formation and destruction", and the French Embassy in Croatia for financial support through "bourse du Gouvernement Français".


Voula Giouli

Aggeliki Fotopoulou

EMOTION VERBS IN GREEK. FROM LEXICON-GRAMMAR TABLES TO MULTI-PURPOSE SYNTACTIC AND SEMANTIC LEXICA

Keywords: emotion verbs, Lexicon-Grammar tables, syntactic structure, distributional properties, semantic classification

We hereby present work aimed at giving an account of Greek verbs denoting emotion that is placed within a larger context, aimed towards defining and describing the semantic field of emotions by means of identifying, selecting, classifying and organizing a core lexicon of emotions in a conceptual Data Base. The ultimate goal is the exhaustive description of Modern Greek and the development of a wide-coverage lexical resource that will be appropriate for a range of Natural Language Processing Applications.

Introduction

This paper describes work in progress aimed at a formal description of the Greek verbs denoting emotion on the basis of formal syntactic and semantic criteria. A core lexicon of emotion verbs extracted from existing lexical resources and corpora has been manually updated and extended where appropriate in order to reflect contemporary lexis and usage. Additionally, linguistic and semantic criteria were employed in order to define the semantic class of emotion verbs formally. The present study focuses only on verbs directly referring to emotional states (e.g. fear, love) as opposed to those having an indirect reference that depends on context (e.g. words that indicate possible emotional causes (e.g. monster) or emotional responses (e.g., laugh cry, etc.)). The so-identified verbs were then studied and classified on the basis of empirical evidence about their syntactic and semantic properties. The ultimate goal being to develop a sound lexical resource (LR) that not only depicts subcategorization information and semantic properties of the verbs, but also comprises a conceptual system that organizes the semantic field of emotions (being, in this sense, an ontology of emotions), the encoding of emotion verbs in a conceptual Data Base (DB) conformant to the underlying theoretical framework was performed.

The Methodological Framework

The theoretical framework adopted within this study is that of Lexicon-Grammar (Gross 1975). Being a model of syntax limited to the elementary sentences of a natural language, the theory argues that the unit of meaning is not located at the level of the word, but at the level of elementary sentences of the form Subject -Verb -Object. This representation is meaningful not only for verbs, but also for nouns and adjectives. To this end, the elementary sentence is being transformed to its predicateargument structure, and the main complements (subject, object) are separated from other complements (adjuncts) on the basis of formal criteria. Moreover, adverbial complements that are considered as crucial arguments in that they characterize certain verbs are also taken into account:

(1) John removed the cups from the table.

To cater for a more fine-grained classification, and the creation of homogenous word classes, this formal syntactic definition is further coupled with distributional properties associated with words, i.e., types of prepositions, features attached to nouns in subject and complement positions, etc. A set of transformation rules, construed as equivalence relations between sentences, further generate equivalent structures. All this information (syntactic structure, distributional properties and permitted transformational rules) is formally encoded in the so-called Lexicon-Grammar tables.

Being initially developed to serve as a means of linguistic description, this framework has, never-the-less, been proved to be applicable for the construction of robust computational lexica. And although it has been claimed (Mathieu, 2008) that the information is not directly exploitable for NLP applications due to the fact that certain pieces of information are not formally encoded or are implicit, a number of works [START_REF] Hathout | Automatic Construction and Validation of French Large Lexical Resources: Reuse of Verb Theoretical Linguistic Descriptions[END_REF][START_REF] Danlos | Constructions pronominales dans Dicovalence et le lexiquegrammaire: Integration dans le Lefff[END_REF] have successfully managed to reformat Lexicon-Grammar tables in efficient large-scale NLP lexica. It becomes evident, therefore, that the Lexicon-Grammar framework together with the requirement of substantial coverage leads to a uniform and consistent description of elementary sentences and the formal encoding of the morpho-syntactic and semantic properties of the predicates across languages in a comparable manner. In this respect, one of the main advantages of Lexicon-Grammar is that it not only allows comparisons between languages both at the lexical and the syntactic levels, but also facilitates the construction of cross-language resources. In this respect, segments of Lexicon-Grammars have already been built for many languages including Greek, and this work may be considered as an attempt to contribute to the description of Modern Greek also in the prospect of the automatic analysis of the language.

3. Defining a semantic class: a core lexicon of emotions Verbs denoting emotion, also referred to in the literature as "verbs of psychological state" [START_REF] Levin | English Verb Classes and Alternations: A Preliminary Investigation[END_REF]) and more commonly known as psych-verbs, have been extensively treated in syntactic theory. Early studies [START_REF] Lakoff | Global Rules[END_REF], [START_REF] Postal | Cross-Over Phenomena[END_REF] have tried to give transformational accounts of the behavior of psych-verbs, whereas (Belletti et al 1988) attempts an analysis of certain properties exhibited by psychverbs in Italian on the basis of their thematic information and syntactic configurations. Other theoretical studies have been engaged with the uniform and consistent description of the lexicon of emotions mainly for languages like English and French (Anscombre 1995), [START_REF] Ruwet | Les verbes de sentiment forment-ils une classe distincte dans la grammaire[END_REF], on the basis of their syntactic properties, lexical choices and semantic criteria. In [START_REF] Jackendoff | Semantic Structures[END_REF], 3 basic semantic classes are defined, which are positioned in the continuum defined as positive (e.g., joy, happiness, etc.), -neutral -negative (e.g., sorrow, fear, terror, etc.). On the other hand, [START_REF] Mathieu | Les verbs de sentiments. De l'analyse linguistique au tratement automatique[END_REF] proposes the classification of French verbs denoting emotion on the basis of their syntactic and semantic properties. In a comparative study, [START_REF] Mathieu | Verbs of Emotion in French and English[END_REF], attempt to reveal properties shared among English and French emotion verbs on the grounds of syntax and semantics. At the same time, the idiosyncrasies of each language are also unveiled.

As far as Greek is concerned, Greek verbs [START_REF] Antoniou | Syntaxe et métaphore des verbes psychologiques en grec[END_REF], [START_REF] Valetopoulos | Ce que vous pensez des autres: La grammaire locale de la jalousie et de l'admiration[END_REF]) nouns [START_REF] Gavrilidou | Détermination des noms de sentiment en grec moderne[END_REF] and adjectives [START_REF] Valetopoulos | Ce que vous pensez des autres: La grammaire locale de la jalousie et de l'admiration[END_REF], denoting emotion have been treated within the Lexicon-Grammar framework. The study hereby proposed, however, will be based on previous work by our research group at the Institute for Language and Speech Processing, that gives an account of Greek nouns denoting emotion [START_REF] Pantazara | La description des noms de sentiments du grec moderne[END_REF] [START_REF] Fotopoulou | La combinatoire lexicale des noms de sentiments en grec moderne[END_REF] from a Lexicon-Grammar perspective. This previous work consists in the classification of nouns denoting emotion based on their syntactical and semantic properties. A grammar was elaborated the focus being on the combinatorics of nouns denoting emotion (85 items) with specific verbs expressing diverse modalities (aspect, intensity, control, manifestation or verbal expression). The long-term goal is the construction of an integrated LR that encompasses nouns, verbs, adjectives and adverbs.

Greek Verbs denoting emotion: selection and classification

After defining and consolidating the core lexicon of emotion verbs, their classification was performed on the basis of their syntactic, distributional and semantic properties as attested in corpus data. For this reason, a subset of the Hellenic National Corpus (HNC), a large POS-tagged and lemmatized reference corpus of the Greek language was employed. To this end, all sentences that contain the verbs under investigation were automatically extracted on the basis of lemma information. Further manual validation of the so-extracted data resulted in the removal of sentences in which the meaning of the verbs at hand was not an emotional one. This corpus was further enriched with a collection of documents originating from various sources over the internet, such as blogs, forums, life-style websites, and from other sources of opinionated texts. The latter data were considered appropriate for this study, since they depict everyday language usage and they reflect some emotional involvement either of the writer or of the discourse participants. The so-collected corpus that currently amounts to c. 300K words also bears annotations at various levels of linguistic analysis: POS-tagging and lemmatization, chunking and dependency parsing. Annotations have been added semi-automatically by means of a Natural Processing pipeline that was developed in-house for the Greek language. Extensive searches in the corpus were performed to verify the usage of the selected verbs.

4.1.Verb selection and initial encoding

Initially, Greek verbs denoting emotion were extracted from Antilexicon [START_REF] Vostantzoglou | Antilexicon i Onomastikon tis Neas Ellinikis Glossis[END_REF]), a concept-based Lexicon for Modern Greek that is in accordance with the lexicographic tradition hallmarked by Roget's thesaurus. More precisely, 1168 verbs and multi-word expressions were identified as lexicalizations of 57 concepts systematized under the semantic class of emotion. This material underwent extensive corrections and modifications catering thus for the exclusion of lemmas or usages that are obsolete. Similarly, multi-word entries were also left out.

At the next phase, a closer investigation over the extracted data, however, revealed a number of entries that are not clear instances of emotion verbs, i.e., verbs directly referring to emotional states of the type αγαπώ (=love), θνβάκαη (=fear), etc. A number of verbs were identified as having only an indirect reference that depends on the context (e.g. words that indicate possible emotional causes as for example βαζίδνκαη (=rely on) or emotional responses (e.g. words that indicate possible emotional responses as θιαίω (=cry), γειάω (=lough), δαθξύδω (=shed tears), etc.). To limit, therefore, the scope of the study -at least at this stage -to clear instances of emotion verbs only, a formal distinction between direct affective words and indirect affective words was in order. To this end, a set of appropriate lexical semantic tests were employed as a formal device guiding the final selection of a core vocabulary of emotions that covers the grammatical category of verbs, and the delineation of the semantic class of emotions, leaving all other cases of semantically and conceptually related verbs for future treatment. As a result, only verbs denoting emotion, or emotional state, as for example αγαπώ (=love), αγαλαθηώ (=resent), ληξνπηάδω (=embarrass), κηζώ (=hate), etc., were assigned a label EMOTION and were selected for further treatment. Building on similar lexicographic efforts adopted by the NLP community [START_REF] Strapparava | WordNet-Affect: an affective extension of WordNet[END_REF]), the remaining entries were assigned a label denoting the relation that links them with a specific emotion. The following labels have been used: EMOTION-ELICITINGSITUATION, EMOTIONALRESPONSE, BEHAVIOUR, ATTITUDE and SENSATION. These entries were left aside for future treatment.

Consequently, the so-produced verb list was further enriched with new entries that were extracted from existing standard lexicographic resources for Greek via synonyms identification. Additionally, specialized electronic resources available for the English language were also consulted, namely FrameNet [START_REF] Fillmore | Building a Large Lexical Databank Which Provides Deep Semantics[END_REF] and WordNet [START_REF] Fellbaum | WordNet: An Electronic Lexical Database[END_REF], and Greek data were supplemented by obtaining translations of the English entries. More precisely, verbs occurring in frames involving an argument of the type Experiencer (that is, a participant characterized as aware of or experiencing something) were considered. Similarly, specific WordNet synsets were also consulted. [START_REF] Levin | English Verb Classes and Alternations: A Preliminary Investigation[END_REF] seminal work on verb classification was also employed. The afore-mentioned process resulted in a list of 339 verbs denoting emotion that were finally selected for further study.

4.2.Syntactic Classification of Greek emotion verbs

The syntactic classification of the verbs was performed on the basis of the following axes: (i) syntactic information (subcategorisation); (ii) selectional restrictions imposed over their Subject and Object complements; and (iii) transformation rules. Elementary sentences of the form subject-verb-essential complements were considered as units for syntactic as well as for semantic composition of emotion verbs. Along these lines, emotion verbs in Greek were identified to appear in both transitive and intransitive constructions being represented as (a

) Ν 0 V, (b) Ν 0 V N 1 , (c) Ν 0 V Prep N 1.
According to the Lexicon-Grammar notation Ν 0 denotes a Noun in Subject position of a given verb V, whereas, N 1 denotes its Object. On the basis of the above-mentioned criteria, four major classes of Greek emotion verbs have been identified which we recall here briefly the definitional constructs: (2) a.

Οη πολίηερ/*Τα βηβιία αγαλαθηνύλ.

The citizens /*The books resent.

b.

Οη πολίηερ αγαλαθηνύλ κε ηα μέηπα λιηόηηηαρ.

The citizens resent (with) the austerity measures.

The citizens resent the austerity measures.

(3) Η ηοπική κοινωνία έθξημε με ηο ζηςγεπό έγκλημα.

The local community shuddered with the heinous crime 2 nd class : Ν0(hum) V (Ε+N1): αγαπώ (=love). This class encompasses verbs with a Ν 0 in Subject position that is obligatorily [+human], whereas N 1 is non-restrictive, in the sense that it can be either [+human] or [-human]. Examples:

(4) Ο Γιάννηρ αγαπάεη ηη Μαπία/ηα βιβλία/ηη μοςζική1 .

John loves Mary / books / music.

(5) *Η μοςζική/*Το βιβλίο αγαπάεη ηον Γιάννη. *The music /*The book loves John.

One basic defining property shared among verbs falling in this class lies in the fact that depending on semantic context, their argument structure may be on occasions reduced by one argument, omitting thus the non-restrictive Object. For example:

(6) a. Γιάννηρ αγαπάεη ηη Μαπία. (transitive)

John loves Mary.

b. Δεν γεννήθηκα για να μιζώ αλλά για ν' αγαπώ. (intransitive) I was not born to hate (I was born) to love.

A second property of this type of psych-verbs is that some verbs in this class possess a passive morphology. Depending on context, these verbs allow for passive transformations:

(7) a. Ανηίπαλοι και οπαδοί, όλοι αγάπηζαν ηον Χούλιο. [+active] Opponents and supporters, all loved Julio.

b. Ο Χούλιο αγαπήθηκε από ανηιπάλοςρ και οπαδούρ. [-active] Julio was loved by opponents and supporters.

3 rd class:: Ν0 V N1(hum) Ν1(hum) V(Ε+PrepN1) : ανησυχώ(=worry). The third class comprises verbs that establish a homogeneous group with specific morphosyntactic properties, as they have only [+active] morphology (λευξηάδω (=pish), αλεζυχώ (=worry), εξεκώ (=calm), etc.) while lacking the [-active] one. These verbs occur in two syntactically distinct, yet semantically equivalent structures, allowing, thus, for inchoative alternation. In the transitive construction, they present an argument structure with Ν 0 in Subject position and Ν 1 [+human] As a final remark, classes (1) and ( 2) project the Experiencer of the emotion as their structural subject and the Theme or Stimulus as their structural object. Similarly, classes (3) and (4) realize the Theme/Stimulus as the subject and the Experiencer as their object, their distinguishing property being their participation in unaccusative and middle constructions, the latter being linked to the implicit presence of an Agent (middle) and the absence of an Agent (unaccusative).

4.3.Semantic classification of emotion verbs

To render the intended resource useful for NLP applications, the classification of verbs in terms of their lexical semantic properties was in order. We aimed at defining a classification scheme that will be applicable for the effective cross-language description of the semantic field of emotions. The approach taken started from a rather coarse classification that gradually takes more fine-grained attributes into account. Following previous works [START_REF] Mathieu | Verbs of Emotion in French and English[END_REF], our scheme initially caters for the polarity of the emotion denoted. Polarity subsumes one of the following values: (a) positive, i.e. verbs which express a pleasant feeling; (b) negative, i.e., verbs which express an unpleasant feeling; and neutral, i.e., verbs expressing a feeling the polarity of which is context-dependent (e.g., surprise).

Moreover, the initial 57 concepts initially identified from the Greek concept-based dictionary, were mapped onto a more concise or coarse schema that subsumes concepts that can be classified under a more generic one, and proper assignments to entries are applied thereof. This classification is centred on a set of 8 basic emotions [START_REF] Plutchik | The Emotions[END_REF]: anger, fear, sadness, disgust, surprise, anticipation, acceptance, and joy. Verbs were further assigned feature strength with possible values: low, medium,and high, catering, thus, for the distinction between near synonyms such as θνβάκαη (= I am scared), παληθνβάιινκαη (=panic), etc.

Encoding in a Lexical Resource

The syntactic classification of Greek verbs denoting emotion has been encoded in Lexicon-Grammar tables that describe formally from a linguistic point of view their argument structure, distributional properties and possible transformations. Each class is represented by a table that includes all lexical items of the class. The properties that are involved in the definition of tables are of three types: syntactic, distributional and semantic. Verbs with more than one usages or meanings, have been treated as separate lexical items, and syntactic and semantic properties are assigned to each meaning thereof (as for example, the verb αγαπώ (=love) and αγαπώ (=like). A set of features that are appropriate for the description of a syntactic category concerning grammatical (i.e., past participle form) or syntactic information (i.e., passive transformation, inchoative alternation, etc.) and lexical choice (i.e., preposition a given verb is subcategorized for) is applied to all entries under consideration, and their linguistic validity was checked on the basis of corpus evidence. At the intersection of a row corresponding to a lexical item and a column corresponding to a feature, the cell is set to '+' if it is valid or '-' if is not.

The lexical database that is being developed also provides information that is common-place to lexicographic projects, i.e., grammatical category, and spelling variants. As it has already been mentioned, during the verb selection process, verbs that pertain to the core lexicon of emotions were assigned a label EMOTION, and were kept in the database for further study. To ensure compatibility and interoperability with standardized tools the final resource will be conformant to widely-accepted standards (Lexical Markup Framework ISO (TC37/SC4)) and will be represented in XML format.

Conclusions

We have hereby presented ongoing work aimed at the formal description and classification of the Greek verbs denoting emotion. The analysis of the empirical data extracted from corpora aims at the development of LR will be applicable for a number of NLP applications ranging from Word sense Disambiguation to text understanding, Natural Language Generation, sentiment analysis, etc. Current and future work concentrates on extending the set of syntactic and semantic properties of the verbs at hand, and to integrate other grammatical categories (i.e., nouns, adjectives) and multiword expressions.

1

  st class:: N0 (hum) V (E + Prep N1): αγαλαθηώ (=resent). This category encompasses verbs like αγαιιηάδω (=rejoice), δυζαλαζχεηώ (=resent), ληξέπνκαη (=be ashamed), θξίηηω (=shudder) with Ν 0 in Subject position being obligatorily [+human]. Examples:

  in Object position. In the intransitive construction, Ν 0 in Subject position is [+human]. Examples: (8) a. Ο Γιάννηρ/ο θόπςβορ λευξίαζε ηη Μαπία /*ηο ζπίηι 2 . John / The noise make Maria / * the house angry. b. Η Μαπία/*ηο ζπίηι λευξίαζε με ηον Γιάννη/με ηο θόπςβο. Maria / * home was angry at John / the noise. (9) a. Η Μαπία/άδικη κπιηική ζύκωζε ηον Μάπιο /*ηην ηαινία. Maria / the unfair criticism made Mario / * the movie angry.

	b. Ο Μάπιορ/*η ηαινία θύμωζε με ηη Μαπία.
	Marios / * the film was angry at Maria.
	4th class:: Ν0 V N1(hum)  : N1=hum Vmp (E + Prep N0): αγχώνω (=stress).
	This class comprises verbs with Ν 0 in Subject position and Ν 1 that is obligatorily
	[+human] in Object position. Verbs in this class take part in either the passive or in
	the middle construction. Examples:
	(10) a. Η Μαπία/οι εξεηάζειρ αγχώλνυλ ηον Γιάννη/*ηο παισνίδι.
	Maria / The exams stress John / * the game.
	b. Ο Γιάννηρ αγχώλεηαη (με ηιρ εξεηάζειρ)
	John is stress.

However, the verb αγαπώ (=love) with [-human] in object position is treated as a separate entry in dictionaries.

Verbs in this category also enter the genitive restructuring property(Guillet el al. 1981), Ο Γιάννησ θφμωςε τη Μαρία [ prep με [ n τη ςυμπεριφορά του] ] = Η ςυμπεριφορά του Γιάννη θφμωςε τη Μαρία (John made Maria angry with his behavior = John's behavior made Maria angry).


Jose Ignacio

Aguilar Río

Cédric Brudermann

Keywords: language learning, language learner, sociocultural language acquisition model, educational endeavour, individual socio-psychological variable

à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

When learning a second language, the learner is first and foremost a social actor, i.e. "un produit constamment restructuré des influences présentes, ou passées des multiples agents de socialisation" (Dubar 2002, 109) whose aim, ultimately, is to gain fluency in and mastery of a given target language-culture (L/C 2), according to the discursive standards "in force" in the area(s)geographical, social, political, or other -in which this code is in use. As such, the L/C 2 "individuapprenant" 1 [START_REF] Bogaards | Aptitude et affectivité dans l'apprentissage des langues étrangères[END_REF] corresponds to a complex and multifaceted entity composed of social, emotional, cognitive and discourse-based variables whose singularity embraces features as varied as his/her own particular identity, personality or cognitive styles and whose purpose is to try to move towards a linguistic and cultural reality which is different from his/her source language(s).

On a pedagogical level, implementing educational endeavours consists in putting tools at the service of the individual-learner (IL) to foster L/C 2 development. As such, the consideration of the ILs' unique variables appears to be "fundamental" (Robinson 2002, 124) for instructional designers and teaching staff when designing and setting up pedagogical artefacts since ILs precisely hold a central place within them, as users [START_REF] Brockett | Self-direction in adult learning: Perspectives on theory, research, and practice[END_REF].

In this respect, it seems necessary to study the conditions under which bridges could be built between social psychology, applied linguistics and second language teaching and learning. Our choice has been to address those links from a socio-psychological perspective. This paper will be an 1 Throughout this chapter, the "individu-apprenant" [START_REF] Bogaards | Aptitude et affectivité dans l'apprentissage des langues étrangères[END_REF]) will be referred to as "individual-learner". attempt to define -as far as possible -who the L/C 2 ILs are and to account for the psychosocial actions that the learning process requires from them.

Social Psychology and the L/C 2 Acquisition/Learning Process

According to Morin/Nair's conception of society (1997,37), the socialization process induces ILs to gradually adopt specific sets of behaviours in order to become social actors of a social group and to be recognized as such by their peers [START_REF] Gardner | Attitudes and motivation in second language learning[END_REF]Bogaards 1991, 53). The process of socialization thus implies an interaction with a given social environment. Through this "language socialization" (###4. Language Socialization), ILs are exposed to the language of their social group -which they eventually may acquire. Developing the competence to use a language -whether it be an L1 or L2 -therefore is a social acquisition [START_REF] Atkinson | Toward a sociocognitive approach to second language acquisition[END_REF]. As such, language acquisition contributes to the development of one's own social identity (###5. Language and Identities) by leading the individual to learn and internalize the social and cultural aspects of a given community and to integrate them into the structure of his/her personality in order to adapt to the social environment in which he/she lives (Rocher 1969, 105). Let us review these concepts and analyse their implications on the second language acquisition process.

Identity

Cohen-Émerique/Hohl (2002,200) understand identity as a twofold concept which encompasses, on the one hand, a personal, self-identity, and, on the other hand, a social one. Both types are involved in one's identity construction and may thus reflect and refer to language-based aspects of the IL. 2 -Personal identity alludes to active and adaptive cognitive functions by virtue of which the IL may come to terms with his/her own person and the world around him/her. This dimension derives both from heredity and neurophysiological maturation on the one hand and, on the other hand, from personal experience. Personal identity has to do with the morphological, physical and physiological characteristics all individuals are endowed with. Personal identity includes, for instance, the ability that human beings have to manipulate language and which requires, in addition to verbal and linguistic aspects both para-verbal elements (e.g. intonation, rhythm of speech and the use of silence) and non-verbal elements (e.g. postures, gestures or attitudes) which play an important structuring and monitoring role in interactional contexts [START_REF] Forgas | Interpersonal Behavior: The Psychology of Social Interaction[END_REF].

These physical attributes give ILs the opportunity to identify themselves, and, in doing so, to grow and to "act" in their environment; 2 Language and identity influence one another (###5. Language and Identities). Our conviction is that a second language modifies the link between language(s) and identity that operates within an individual [START_REF] Norton | Identity, Language Learning, and Social Change[END_REF].

those associated with the language learning processes (Norton/Toohey 2011).

However, in order to interpret and act upon their social worlds, to come to terms with the social environment in which they live, and to direct their social practices, ILs will be sensitized to the social and cultural aspects of the community, in order to accommodate them (Rocher 1969, 105). Such accommodation does not necessarily entail the ILs' adherence to specific practices or values, but, rather, their capacity to identify these as such, even though they may however decide not to implement them.

Personality

The ILs' personality can be characterized as a consistent, fundamental set of traits or tendencies [START_REF] Allport | Trait names: a psycho-lexical study[END_REF] which account for ways of functioning socially, regardless of time or context.

In turn, the personality traits will influence the way in which individuals perceive events and their environment.

The personality traits of an IL have an impact on him/her when learning an L/C 2, not only in terms of the way s/he will perceive the L/C 2, but also as regards his/her attitude towards it. 3 The integration of the theories of personality within a language learning pedagogical framework seems convenient to avoid the consequences that the various traits can have on the L/C 2 teaching and learning practices:

- Bogaards (1991, 61), for example, indicates that oral comprehension is related to an individual's enterprising and sociable character, to extroversion and the absence of neuroticism, and that rather outgoing and stable ILs tend to get the best results in oral comprehension and expression. It follows that extroversion would be an important asset to reach a "good" performance level in oral expression (Brown 1973, 236;cited by Bogaards 1991, 64); -In contrast, ILs showing introverted personalities (Cheng/Horwitz/Shallert 1999), and who would not manifest a particular "willing(ness) to communicate" in their first language(s) would be even less prone to do so in an

L/C 2 (MacIntyre 2007).
These examples suggest that the personality traits are part and parcel of a complex system built around the ILs, and include self-based constructs such as one's self-concept, attitude and beliefs, which ILs have about themselves and whose influence on the L/C 2 acquisition process is now beyond a doubt [START_REF] Arnold | Comment les facteurs affectifs influencent-ils l'apprentissage d'une langue étrangère?[END_REF]).

3

We do not regard "second language-culture" as two separate elements, but, rather, as a twofold, mutually determining ensemble.

Self-based constructs

Three self-based constructs will be taken into account for our characterization of the ILs. These are: self-concept, attitude, and self-esteem. Godefroid (2001, 626s.) defines the "self-concept" as the self-knowledge the individual possesses, which grants him/her "une certaine stabilité interne, en la protégeant contre les changements, mais également une flexibilité suffisante la rendant capable de s'adapter, lorsqu'elle est confrontée à son environnement social ou qu'elle est amenée à prendre des décisions" -what [START_REF] Norton | Identity, Language Learning, and Social Change[END_REF] call "investment" in the case of L/C 2 learning. Any learning experience entails a process of personal development, which may have an impact on the IL's self-concept. It is up to the actor who occupies the tutoring position to account for this, in order to develop a mediating pedagogy suitable for the IL's objectives -namely by accompanying the discovery of his/her very self-concept(s).

Self-concept

Attitude and L/C 2 teaching-learning

The concept of attitude includes emotions (###17. Cognition and Emotion) -which fall within the area of affect [START_REF] Triandis | Values, attitudes, and interpersonal behaviour[END_REF]) -such as joy, pleasure, disgust, discontent and hatred -which ILs will associate with certain behaviours and which will influence their psychological disposition to act toward a given object, namely an L/C 2. The IL's behavioural intent is besides also determined by his/her subjective standards concerning a given behaviour s/he would happen to adopt within an L/C 2-use situation.

If we refer to Fishbein and Ajzen's theory of reasoned action (1975), this belief-based mechanism would have a direct effect on the IL's attitude and on his/her behavioural intention(s) (cf. Figure 1) -as suggested in the figure below:

Figure 1: The theory of reasoned action by [START_REF] Fishbein | Belief, attitude, intention and behaviour: an introduction to theory and research[END_REF] According to Castellotti/Moore (2002, 11), the negative image a learner may have about a specific community -the authors suggest the negative attitude that French learners may have towards Germany as a country -may support the negative vision of an L/C 2 that is difficult to learn. On the opposite, [START_REF] Jones | The Ulpan in Wales: A study in Motivation[END_REF] shows how intensive courses of Welsh -mainly addressed to young learners who strongly feel they belong to the Welsh community -may lead to higher levels of acquisition in comparison with neutral L/C 2 contexts -where a lesser feeling of belonging would be observed.

As a matter of fact, the IL's feelings and judgements influence the way s/he will collect, integrate, and make sense of any situation and any learning object.

Self-esteem

Self-esteem is primarily emotional (Leary/Downs 1995, 134). If one individual's cognitions about his/herself are not consistent with what that individual's actions suggest as his/her current competences in a given matter/practice, there is a great chance that the IL's self-esteem will not reflect reality [START_REF] Epstein | Cognitive-experiential self-theory: an integrative theory of personality[END_REF]. For example, an individual can lack self-esteem and thus forget about his/her strengths, e.g. when an IL reckons s/he is experiencing L/C 2 learning difficulties at school while s/he is instead having difficulties making a difference between two sounds 4 , the IL could thus be led to underestimate the other skills s/he has because of this particular problem. The influence of an IL's beliefs on his/her learning process is significant (Cotterall 1995, 195). As the ILs' selfesteem and beliefs can also predict their learning outcome [START_REF] Harter | Developmental perspectives on the self-system[END_REF], it is important, on a pedagogical level, that the IL's self-knowledge be as accurate as possible, possibly through the mediation of a tutoring third party.

Social psychology, L/C 2 acquisition and pedagogical implications

Whatever the nature of the educational artefact, Bogaards (1991, 100) reminds "qu'il y ait apprentissage ou non, cela dépend de l'apprenant" and that "l'enseignant ne peut que mettre en place les conditions favorisant l'apprentissage […] se mettre au service de l'apprenant qui, lui, peut profiter de ses services, ou non".

As an IL's profile -behavioural, discursive, psychological, social -may vary over time, the particular social and psychological constructs discussed above may be more or less salient and their influence on a learning situation may evolve. Nonetheless, it is useful, for pedagogical supervision purposes to take into account these constructs, as well as the ILs' beliefs and attitudes, in order to 4

For instance, native Spanish-speaking learners of French find it difficult to distinguish [u] and [y]. This difficulty concerns both their ability to perceive the acoustic and articulatory differences between the two phonemes, and consequently to implement such differences into their own production -both on segmental and supra-segmental levels.

positively accompany their development. This may be achieved by giving them the opportunity to be in situations where they will do well, particularly at the early stages of the learning process [START_REF] Bandura | Exercise of personal and collective efficacy in changing societies[END_REF]. Indeed, the first attempts when learning an L/C 2 are the most delicate ones, insofar as they play a key role in one's construction of a sense of competence and, in turn, determine the ILs' subsequent involvement in similar tasks (Kanfer/Ackerman/Heggestad 1996) (cf.

Figure 2). Measuring these variables, as well as their likely influence all along the L/C 2 development process, is consistent with pedagogical approaches based on sociocultural theories, which adhere to a non-linear, complex, and evolving characterization of all learning processes (Larsen-Freeman/Cameron 2008). Figure 2 shows that, following [START_REF] Rogers | On Becoming a Person[END_REF], having a positive self-image helps to gain confidence and be successful in a learning situation and that, conversely, a negative self-image causes low selfesteem and failure. Teaching ILs how to "self-regulate" [START_REF] Wenden | Metacognitive knowledge and language learning[END_REF], that is to say, take control of their learning process and procedures, appears to be an educational approach to promote since becoming responsible for one's learning process favours autonomy.

Individuation/Socialization vs. L/C 2 Teaching-Learning

So far, we have characterized the language learner as an individual whose social and psychological traits determine whatever language-learning endeavours. We have suggested the link among such social-psychological constructs and any learning experience. A learning process of a "foreign" language and a culture, different from those said to be the native ones, may thus be defined as yet another process of internal change 5 which may lead -or aim -not only to develop new skills, but also to promote changes in the IL's constructs, values and beliefs [START_REF] Mezirow | A critical theory of adult learning and education[END_REF].

The development process of an L/C 2 is currently described by second language acquisition (SLA) emergentism theories as a dynamic system (###6. Language Acquisition Theories). The focus is on all the elements which integrate the system, rather than on isolated parts of it. Any changes undergone by one of the identified variables will affect the whole system. The only thing that can be predicted about the system is that it will be led to change. Consequently, according to emergentist theories, the only thing that can be predicted about a language learning process is that learning there will be -it remains difficult to predict what will become the object of such learning, when this learning will take place, or by virtue of which actions it will be brought to happen (Larsen-Freeman/Cameron 2008).

Models of L/C 2 learning: language-based and individual-centred approaches to SLA

Learning an L/C 2 implies for the ILs not only managing new sets of discourses and practices, but also operating in a field of action whose social and cultural structure are different from the one(s) in which they originally developed. This, in turn, may lead to a certain destabilization. Learning an L/C 2 therefore induces having one's personal identity undergo a process of acculturation [START_REF] Schumann | The acculturation model for second language acquisition[END_REF], i.e. gradually moving from a sense of belonging to a group (associated with cultural practices and a cultural background) with which the learner self-identifies to a more open one including (an)other group(s) normally representing otherness. The result of this process is a "new" sense of belonging and a multiple identification.

As a matter of fact, learning an L/C 2 requires the ILs to "renegotiate" themselves, by integrating into their self-concept (formed in one or more L1) the vast notion of otherness, namely the variables "foreign language" and "foreign culture" of the L/C 2, to which they attempt to be open. In this respect, two major trends can be distinguished in SLA: a cognitive SLA model and a sociocultural one (###6. Language Acquisition Theories). According to Foster/Ohta (2005, 402ss.) cognitive SLA perceives learning as a mental process through which morphosyntactic, phonological and lexical structures are integrated, while, in the sociocultural perspective, learning is seen as a social process in which the context and the participants are inseparable. In effect, scholars within the social-cultural theories paradigm draw on [START_REF] Vygotski | Mind in society: the development of higher psychological processes[END_REF] notion of scaffolding to explain the pedagogical bond between two individuals. By virtue of this bond, the learner may undergo a learning experience (Bruner 1998) (###6. Language Acquisition Theories).

5

One of the first being the learning of the mother tongue(s).

The cognitive SLA model of L/C 2 learning

According to [START_REF] Firth | Second/Foreign Language Learning as a Social Accomplishment: Elaborations on a Reconceptualized SLA[END_REF], the pedagogical approaches originating from cognitive SLA models may fail to address the complex relation between learning and identity. Learning an L/C 2 may accordingly be seen as detrimental to "l'image de soi, à la conscience de soi en tant qu'être unique en continuité avec soi-même" (Cohen-Émerique/Hohl 2002, 199s.). It follows that the L/C 2 learning outcome -in acquisitional terms -depends, in addition to factors inherent to the ILs, on how they conduct and are involved in their learning process, on the way they are led to learn, or on their beliefs regarding the target L/C 2. A clarification of the role of the personality variables and their influence on the ability to succeed in an L/C 2 learning endeavour is necessary because noncognitive influences would have an impact which would be, in this approach, at the very least equal, not to say more important in the L/C 2 learning process (Sparks/Ganschow 2001, 100).

In effect, Firth/Wagner (2007, 801) are critical towards cognitive models. According to these authors, such models mainly focus on the linguistic and pragmatic failures of the ILs -who are regarded as faulty interlocutors, insofar as their only identity choices are to be made among native and non-native (Firth/Wagner 1997, 292).

The sociocultural SLA model of L/C 2 learning

Sociocultural SLA models take into account not only language and discourse-related phenomena, but also social and psychological factors. For those who adhere to sociocultural SLA models, L/C 2 learning requires the implementation of specific, specialized (Firth/Wagner 1997, 292) social practices, and also the carrying out of human actions, the performance of social practices and the embodiment of identities (Mondada/Pekarek Doehler 2004, 504). A process which goes beyond abstract, linear and cumulative perspectives on language learning (Firth/Wagner 2007, 804), and which requires a permanent construction, which is accomplished collectively and publicly through one-off activities, within social contexts (ibid., 807).

Close to this position, Ellis (2003, 181) highlights how sociocultural SLA -through the concept of scaffolding -offers a more complete view of learning than cognitive SLA: while the second view focuses exclusively on the cognitive aspects involved in the L/C 2 learning process, the first also encompasses emotional or personal aspects, which highlights, once more, the possible influence which self-image might have on cultural patterns in the case of a theory for learning an L/C 2.

The L/C 2 learner at the heart of an autonomous learning process

The distinction aforementioned between cognitive and sociocultural models of SLA will induce us to reflect on what may be acquisitionally and pedagogically appropriate L/C 2 learning environments -which account for both psycholinguistic and social-psychological constructs and processes. These environments will lead us to focus on the tutors' responsibilities within institutional learning contexts.

ILs' self-based constructs, autonomous learning and socioconstructivism

From a sociocultural point of view, the role of teachers and education, as far as ILs are concerned, is to help accompany the latter towards autonomous practices liable to assist them in their own learning processes (Narcy-Combes 2005). In the case of L/C 2 teaching-learning, this entails having ILs to:

be actively in charge of everything that is related to the learning process, that is to say its definition, its management and its evaluation [START_REF] Holec | Autonomie de l'apprenant: de l'enseignement à l'apprentissage[END_REF] and this is all the more true for adult learners since, for them, self-learning and personal responsibility are strongly encouraged [START_REF] Candy | Self-direction for lifelong learning: A comprehensive guide to theory and practice[END_REF]; take the responsibility for their own learning -i.e., the ILs' personal commitment to act according to specific social values that favour a collective endeavour, such as an institutional learning process. As such, a learning environment based on a collaborative pedagogical approach, calls for a contract that binds the teacher and the learners.

In this respect, we agree with Henri/Lundgren-Cayrol ( 2001), for whom collaborative learning is a "démarche active par laquelle l'apprenant travaille à la construction de ses connaissances" and for whom a collaborative learning environment must comply with certain principles:

the knowledge is to be explored and broken down into distinct elements, rather than become an object that learners take in as a whole; learning is to take place within realistic, authentic situations; the ILs are to actively and continuously interact with one another;

their autonomy and interactive efficiency must be developed progressively;

the higher-level competences -analysis, synthesis, problem solving, etc. -should be encouraged; the (meta)cognitive strategies are to be fostered in order to exploit efficiently the cognitive resources available; the ILs are to engage within the group, and to share common objectives; they are expected to support each other.

The last of the above principles is reminiscent of [START_REF] Jermann | Conception et analyse d'une interface semi-structurée dédiée à la corésolution de problèmeproblem[END_REF] characterization of a "good" learning environment, which allows for the learners to access a community of experts able to guide and counsel them and where knowledge is co-constructed within real experiences, by means of language, accounting for the interactants' personal development [START_REF] Bucheton | Interactions: co-construction du sujet et des savoirs[END_REF]. This raises the questions of feedback and mediation in the SLA process.

Collaborative learning and mediation

Mediation is a central tenet to the constructivist approaches to learning [START_REF] Vygotski | Mind in society: the development of higher psychological processes[END_REF]. As regards L/C 2 learning, two levels of mediation may be distinguished:

between the knowledge and the learners; among the learners themselves.

Mediation requires a third party to accompany the ILs' reflective process(es). It seems appropriate to gauge the mediation according to the competences the learners have already acquired. These may, in effect, not only be the starting point for the mediator's task, but also contribute to ensuring that the ILs engage within an active process of personal development -we consider that all learning is a process of personal development. The mediator's role in this perspective is not only to encourage the scaffolding process (Bruner 1998) but also to invite the ILs to surpass it, so they may engage within a collective process of knowledge construction.

Situated learning and L/C 2 learning

According to [START_REF] Lave | Situated learning: legitimate peripheral participation[END_REF], learning is a social practice, which results from the interaction and negotiation carried out by the members of a particular community of practices. As regards L/C 2 learning, this theory suggests that learning may only occur if the learners engage within a socially and culturally structured context. Interactions may thus allow ILs to identify the meaningful characteristics of the L/C 2, the differences between their mother tongue(s) and the L/C 2, but also between his/her present capacities and the L/C 2 norms, as observed in the input to which s/he is exposed (Robinson 2002).

If learning is understood as a situated practice, it follows that it results from the accomplishment of activities which have been collectively determined by all participants. This position accounts for the social constructivist approach of the human and of social interaction.

Situated learning and information and communication technologies

Information and communication technologies (ICT) seem to be relevant tools to materialize situated learning. ICT make it possible to design and implement complex, authentic and meaningful situations, which enable the learners to draw on their resources in order to construct collectively their knowledge, solve problems and develop their competences, as they position themselves within a common realm of knowledge and practice by using the same communication code (both verbal and non-verbal) which will enable their recognition as members of the community by the other participants. The learners gradually construct their own learning process as they "thrive" within a given community of practice. Provided that the learners are able to manage the changes, this will, in due time, make their integration within the community possible [START_REF] Lave | Situated learning: legitimate peripheral participation[END_REF].

Situated learning and pedagogical implications

Considering what has been stated so far, and from an institutional, educational level perspective, it appears that setting up knowledge-construction communities [START_REF] Hewitt | Design principles for distributed knowledge building processes[END_REF] where the learners may adequately co-construct their own knowledge, is appropriate as far as learning facilitation is concerned. In order to recreate the required authenticity within institutional learning environments, it is possible to situate teaching within macro-contexts that favour the exploration of knowledge from multiple points of view [START_REF] Spiro | Cognitive Flexibility, Constructivism, and Hypertext: Random Access Instruction for Knowledge Acquisition in Ill-Structured Domains[END_REF]. A project-based approach to teaching is coherent with a social-psychological characterization of ILs, insofar as it accounts for the ILs as "'social agents', i.e. members of a society who have tasks (not exclusively language-related) to accomplish in a given set of circumstances, in a specific environment and within a particular field of action" (Council of Europe 2001, 11). The table below synthesizes the different pedagogical implications resulting from our alignment with the social constructivist theories.

Learning

Pedagogical implications Learners' functioning

The objective of the learning situation is to have the ILs deeply restructure their former knowledge [START_REF] Fabre | Situations-problèmes et savoir scolaire[END_REF].

ILs must be at the heart of an environment that aims for the integration and acquisition of both contentknowledge and skills [START_REF] Holec | Autonomie de l'apprenant: de l'enseignement à l'apprentissage[END_REF].

It is not possible to predict in which ways the learners will/may learn [START_REF] Beillerot | Savoir et rapport au savoir[END_REF]).

The institution must aim for the learners' autonomy [START_REF] Duquette | Analyse de données en apprentissage d'une L2 en situation d'autonomie dans un environnement multimédia[END_REF].

The learning environment must help create a favourable context which facilitates learning.

ILs are expected to actively take the responsibility for their learning [START_REF] Holec | Autonomie de l'apprenant: de l'enseignement à l'apprentissage[END_REF]. As for the teacher, s/he keeps the chief responsibility for setting up the learning environment, as well as for gradually accompanying the learners towards an acceptance of their own responsibility [START_REF] Smith | The promise of learning to learn[END_REF]).

The learners are expected to renegotiate themselves, i.e., they are expected to integrate within their core, personal, structure -built from other language(s)the "language" and "culture" based elements Collaboration and scaffolding-based learning theories (Bruner 1998), seem an adequate pathway to set up pedagogical environments aiming at making language ego boundaries more permeable [START_REF] Guiora | Personality and language behaviour: a restatement[END_REF].

A pedagogical approach based on the collaboration and scaffolding, makes it necessary for an external agent to mediate between the learner and the learning process [START_REF] Vygotski | Mind in society: the development of higher psychological processes[END_REF].

ICT help set up authentic, situated, learning environments. The learners who take part in these environments may mobilize their resources, as well as co-construct new knowledge, and develop their skills.

Such a development process may in turn grant them the acceptance of those who are recognized as full-time members of the community of practices for which the L/C2 learners aim.

Conclusion

This paper has portrayed the IL as an actor who functions socially, categorizes and is categorized in more than one language. As such, the IL has particular ways to situate her/himself within the different communities of practice to which s/he belongs, and also within which s/he aims for. The ILs are thus able to:

process (receive, decode, encode, produce, retrieve, mistake, repair, contrast, compare, ...) temporary, constantly changing information in real time;

modify, adapt, develop the (material, cognitive, social, human, strategic, economic, knowledge-based, technical, language-based) means by which s/he is able to process temporary, constantly changing information;

functionally occupy a place and play specific roles within (a) given (geographical, political, historical, moral, ethical, social, communitarian, economical) This point having been made, it follows that the characterization of any language learner may not ignore personal and psychological aspects such as the IL's identity development. The identity development process includes complex aspects such as psycho-social constructs (e.g. gender, surname and first name, profession, age, etc.), the beliefs that the individual may integrate consciously (of a religious or ideological nature, for example), the psycho-cultural practices which the individual will regard in a certain manner (e.g. customs and rituals, cultural expressions and codes, etc.), the personal stories which shape the IL's life experience or the beliefs about one's personal traits (personality, intelligence, aptitudes, skills), physical appearance (health, physical condition, attractiveness), social relations (with family members, friends, work colleagues, and even with opponents), and also about the roles that the IL recognizes as his/her own (student, learner, accountant, teacher, engineer, …).

From a general learning perspective and, consequently, from a culture and language learning point of view, it is crucial to integrate these social and identity-related aspects within a learning environment (###5. Language and Identities), for any social situation will provoke an emotional response from the individual, which s/he may recognize as adequate and specific to the situation in course (for example, learning or using an L/C 2 within an institutional learning environment) (Narcy-Combes 2005, 12). Consequently, the complex, individual and social networks depicted in this article shall be taken as the departure point for all educational endeavours, particularly when adults are concerned.

Learning an L/C 2 is not only a matter of learning linguistic aspects, but also social, pragmatic, civilization-related, diachronic, or synchronic ones, for example, as it supposes a process of personal development along which the IL will broaden aspects of his/her own identity and personality. The depiction of language learning that we have attempted here is more encompassing insofar as it takes into account the identity-development process, which has an impact on both the teaching and learning tasks, and as a consequence, on the L/C 2 acquisition process.

Figure 2 :

 2 Figure 2: Beliefs and L/C 2 learning-teaching

Table 1 :

 1 Social constructivism and L/C 2 learning/teaching

  locally and sustainably modify, adapt, develop the (material, cognitive, social, human, strategic, economic, knowledge-based, technical, language-based) means by which s/he imagines, constructs, chooses, renews, refuses, tries out, implements, attempts, succeeds, fails, attempts anew, abandons, exports, imports (personal, collective) objectives within the local context(s) s/he happens to occupy.

	evolving context(s);
	-locally position her/himself (ideologically, emotionally, politically, morally, ethically, psychologically) in
	relation to the temporary context(s) s/he happens to occupy, in which s/he may play roles, and relate such
	position(s) and role(s) to former, parallel, other position(s) s/he may occupy and roles s/he may play;
	-locally and sustainably imagine, construct, choose, renew, refuse, try out, implement, attempt, succeed, fail,
	attempt anew, abandon, export, import, (personal, collective) objectives within the local context(s) s/he
	happens to occupy;

-

Cheng, Yuh-show/Horwitz, Elaine/Schallert, Diane (1999), Language Anxiety: Differentiating writing and speaking components, Language Learning 49, 417-446. Cohen-Émerique, Margalit/Hohl, Janine (2002), Menace à l'identité chez les professionnels en situation interculturelle, in: Colette Sabatier/Hanna Malewska-Peyre (edd.), Identité altérité et acculturation, Paris, L'Harmattan, 199-228.Council of Europe (ed.) (2009), Common European framewoek of reference for languages: Learning, teaching, assessment, in: