F Montmessin
email: franck.montmessin@latmos.ipsl.fr

T Fouchet

O Korablev

S Rafkin

S Rodriguez Bustabad

F Lefèvre

T Foujols

J.-M Reess

A Maattanen

F Henry

P Bernardi

I Arruego Rodriguez

D Belyaev

J.-L Bertaux

E Chassefière

P Drossart

S Erard

A Fedorova

F Forget

V E Hamilton

D M Hassler

A Hauchecorne

E Lellouch

E Marcq

The Mars InfraRed Trace Gas Investigation Spectrometer (MIRTIS) for the 2016 Exomars Trace Gas Orbiter

MIRTIS is dual spectrometer aimed at characterizing trace gases in the atmosphere of Mars. It operates in the near-and mid-infrared and shall provide unprecedented sensitivity for the detection of trace gases with geophysical and/or biological origin.

Instrument description

The Mars InfraRed Trace Gas Investigation Spectrometer (MIRTIS) is a compact, high-heritage instrument that has been designed to comprehensively address the three Science Objectives of the 2016 ExoMars Trace Gas Orbiter (TGO), whose announcement of opportunity has recently been released jointly by ESA and NASA. The MIRTIS instrument is the combination of a midinfrared (MIR, see figure 1) and a near-infrared (NIR) channel that both operate in nadir and solar occultation modes. The MIR channel is a crossdispersion spectrometer that covers simultaneously the 2.3-3.8 µm range with a mean spectral resolution of 11,000 and a signal-to-noise ratio (SNR) of 500 (per 6 second exposure) in nadir and 3,800 (per second) for solar occultation. The NIR channel is based on Acousto-Opto Tunable Filter (AOTF) technology that sequentially scans the 0.7-1.7 µm range at a spectral resolution of 1,300 and with a SNR ranging between 400 (nadir) and 800 (occultation). Leveraging high heritage from experiments currently flying on Mars and Venus Express, Rosetta, MIRTIS is dedicated to the following scientific objectives:

1) Detection and inventory of trace gases on Mars

The recent detection of CH4 has reignited interest in the possibility of past or extant life even though an abiogenic origin is also plausible. Regardless of origin, this discovery suggests that Mars is still an active planet, contrary to common perception. An intriguing aspect of the observations is that CH4 appears to be locally enhanced, up to 45 ppbv, and to change with seasons. Owing to its supposed 300-year lifetime, this short-scale variability is at odds with the current understanding of chemistry and physics87. Furthermore, Earth-based and PFS/MEX measurements show very different CH 4 maps and variability. A first priority is therefore to confirm the presence of CH 4 by performing a high-sensitivity search throughout the atmosphere of Mars. With a detection limit (after co-adding) of 10 pptv in solar occultation and 100 pptv in nadir, MIRTIS is able to quantify the abundance of CH 4 with unprecedented sensitivity. In addition to CH4, MIRTIS will search for and quantify the abundance of a suite of gases listed by the Joint International Definition Team report: 13 CH 4 , C 2 H 2 , C 2 H 4 , C 2 H 6 , CH 2 O, H 2 S, OCS, N2O, HCl, HCN. MIRTIS can improve detection capabilities over previous investigations by at least one and up to several orders of magnitude (figure 2).

2) Characterization of trace gas distributions

The nadir mapping capability of MIRTIS can provide a global view of the spatial and temporal variability of trace gases, with sensitivity all the way down to the surface level, even under conditions of high dust loading (see Figure 3). Concurrent mapping and vertical profiling of standard climatic variables (dust, clouds, temperature) will relate the trace species to their environmental context.

3) Sinks and sources: localization and quantification MIRTIS has the capability to fulfill the geographical and temporal coverage requirements needed to identify the sinks and sources of trace gases on Mars. The MIRTIS mid-infrared channel allows identification and quantification of all targetable species simultaneously, which is needed to estimate the oxidation rate and the lifetime of chemical species by both homogeneous and heterogeneous processes. Depending on the gases observed, or through ratios with isotopologues, fundamental information on the nature of the source (biogenic vs. abiotic) will be obtained.

Figures

Figure 1 :

 1 Figure 1: MIRTIS MIR channel layout.

Figure 2 :

 2 Figure 2: MIRTIS sensitivity in occultation for various gases and different dust backgrounds.

Figure 3 :

 3 Figure 3: CH4 (10 ppbv) spectral region observed by MIRTIS under various conditions of dust. Dust has negligible effect on methane band strength and structure, making nadir viewing a very robust way to detect methane.


Valérie Cohen-Scali-Cnam

Introduction

In the current context of the Anthropocene, individuals and organisations must change their behaviour to stop taking resources from natural environments, to stop emitting carbon monoxide and methane, and to reduce and recycle all waste. Today, we are still far from the objectives of the 2015 Paris Agreement signed by 195 nations. As the IPCC reports state, if global emissions continue at their current level, warming is expected to have exceeded 2° by 2050 with even more disastrous consequences. We can see how difficult it is to change habits and priorities. Every day, we see the existence of multiple blocking points and resistance to the implementation of new practices, including the ecological transition.

This paper aims to question the role of companies and HRM practices in these changes. I will first discuss the structural tensions that companies are currently experiencing, then I will present the results of a study on the representations of company managers, and I will conclude with some thoughts on the possible contributions of career counsellors to changing these perceptions and practices in developing interventions for future and current workers.

I -Tensions between companies and employees

There is a great deal of research on individual and organisational change and it has often been shown that the objectives of employees and organisations only partially overlap.

But today we are in a more complex period where the gap between the intentions and objectives of organisations and those of employees is growing. This is a major tension that our companies are experiencing, and which constitutes a major obstacle to the concrete implementation of the ecological transition. Indeed, organisations have been in crisis since the 1970s (Segrestin and Hatchuel, 2012). While before the 1970s, companies embodied technical inventiveness, professional community, a space for negotiation and the construction of skills, since the 1980s, they have entered an era of financialization which destroys their initial mission of producing common goods, establishing a place for collective life and the construction of professional identities. Today, shareholder value has become the dominant criterion of performance and the strategic compass of managers. This is why capital income has been exceptional since the 1980s. But this progression is at the expense of companies' capacity for innovation and social justice; sociologists Segrestin and Hatchuel suggest that companies are currently experiencing an identity crisis that requires a rethinking of the foundations of what a company should be in a society which is in ecological transition.

While companies are focusing all their attention on shareholder satisfaction, employees are experiencing a crisis in the meaning of work, which is also a crisis in their professional identity (Dubar, 2000). In a 2019 survey by the French Ministry of Labour (DARES), only 14% of employees said that they always have the opportunity to do things they enjoy in their work, 17% said that they always have the opportunity to develop professional skills, 20% always have the opportunity to work at their own pace, 20% always have the feeling that they are doing a good job (Survey of working conditions, according to a study by Coutrot and Perez, 2022, involving 14,231 people). This is a minority. In 2021, another survey on the consequences of the pandemic crisis (Beatriz et al., 2021) showed that more employees felt that their work was in conflict with their ethical principles after the crisis than before. In addition, more and more employees today feel that their work is damaging the environment.

More people are considering changing jobs or careers. Thus, 5 million employees quit their jobs every month in the US since the beginning of 2021, a phenomenon referred to as the Big Quit or the Great Resignation. In China, the Tang Ping movement ("lie down on the floor") appeared in the spring of 2021 on Webo (the Chinese twitter) and calls for "lifting the foot". In France, resignations are increasing, especially in the health sector, and recruitment problems are very significant. Among the employees who resign, many turn to ecological jobs.

A growing number of employees are rejecting companies and are turning to self-employment, the social and solidarity economy sector or the craft industry. But what do managers think about this situation? How do they see the future of their company?

II -Research on representations of the future by company managers

In this research project, we wanted to explore the attitude of managers towards major societal changes and in particular the ecological transition. We wanted to know:

-What place this question had in company strategies -To what extent the question of the meaning of work was taken into account -Whether new soft skills were expected in the future in order to integrate new forms of relationship to work and new ways of living and of producing in the company Soft skills are the competencies most often mentioned by companies because they are supposed to allow employees to face the major challenges of tomorrow's world of work. For this purpose, we referred to the competency frameworks disseminated by international organizations and called "21st century competencies". As point of comparison, we chose the Fullan and Langworthy (2014) referential which considers 6 families of competencies useful for the future: Education of the person (Education of character) /Citizenship/Communication/Critical thinking /Collaboration/Creativity. We wanted to know if these various competencies would be mentioned, which would perhaps mean an evolution, a taking into account of certain social values, of the ecological transition by certain companies and thus a degree of openness on the social dimension of the company.

Methodology Participants

A total of 30 semi-structured interviews were conducted with managers of 18 organizations in industry and culture and sport.

We interviewed management professionals and HR professionals.

Tools

Participants were asked 3 main open questions and then completed a questionnaire presenting a list of soft skills often mentioned in the literature. They were asked to order each one from 1 (important) to 3 (not important).

1/ What major challenges are facing their company 2/ What are the consequences on employees' careers 3/ What soft skills are needed for the future regarding these changes

Data analysis

Consensus thematic content analysis and lexical metric analysis.

Six researchers were mobilized to define the content analysis grid, categories and subcategories.

A grid with 3 main themes was developed:

1.

-The major changes taking place in the company 2.

-The consequences on HR management -Increased constraints on work (13 out of 30) (decrease in raw materials, budgetary restrictions, obstacles in the development of projects).

B/ Changes linked to digitization (28 out of 30)

-Appearance of new professions, new professional gestures, reconfiguration of the market with development of online products.

C/ Changes related to external factors (30 out of 30)

-Economic changes (Olympic games) (28 of 30)

-Ecological transition (mentioned by 17 out of 30) mentioned above all in industry "we want to see how each department of the company takes ownership of the ecological issue"

"It becomes an opportunity for companies to join the ecological transition movement as a factor of economic opportunity".

-Political changes (14 out of 30), in particular the often-mentioned Ukraine conflict.

2/ How HR management adapt to these changes

A/ In developing future training for employees Vocational training as a major issue but which must, above all, be "profitable" and in the interest of the company's needs (25 out of 30), targeting employees "with potential" and middle-managers -Individualized and personalized training (13 out of 30) and promoting collective work (21 out of 30).

-

Work organization:

-For their workstation: autonomy, organization/planning, knowing how to manage themselves, knowing how to self-assess, mastering basic knowledge, staying focused -For the work of others: knowing how to delegate, being fair and consistent in the way you evaluate, motivating others, planning activities, identifying individuals with potential, enhancing the ability to dialogue.

On the other hand, nothing on critical thinking, citizenship 4/ Answers to the questionnaire (importance), rank no. 1 being judged to be the most important for the entire population.

Table

Discussion

-The ecological transition was mentioned by half of the interviewers -The feeling of a change in the employees' relationship to work but no avenues mentioned on how to solve the problem.

-Secondary mention of the importance of critical thinking skills or citizenship.

-The training courses envisaged are related to Corporate Social Responsibility, showing that managers are aware of the importance of spreading these ratings among the employees.

Quite classic expectations of profitability and performance, of employees who must adapt quickly.

An investment in managerial staff, who appear to be central and who are more highly trained than other technical or manual employees.

What types of practices need to be imagined to change the mindset and representations of managers? How could they integrate ecological transition issues into their practices?

How can they develop an in-depth reflection about production and consumption to enable society to enter a post-industrial and post-growth period?

I would like to mention several ideas:

The younger generations are taking charge of companies and can instil a new green mindset among the management. Career counselling interventions should not only focus on selfconstruction but also integrate ecological and social construction and consider their ability to change people' attitudes.

-Young people, as well as managers and executives, must have the opportunity to engage in in-depth reflection on the role of the company in society though workshops. More collective and democratic forms of management where employees have an important place in the decisions will have to be considered by future professionals.

-Young people must have the opportunity to reflect on the fact that a diversity of organizational forms exists and not only organizations focused on shareholder profit. For example, there are activity and employment cooperatives, associations, and self-organized "liberated" companies, NGOs.

-Career counsellors can also intervene in youth training programs. Curricula must all include the ecological transition, systemic, interdisciplinary and global approaches, collective learning and projects in co-construction with teachers and organization stakeholders should be considered, Life Design workshops aiming at the development of reflexivity and critical thinking should be developed.

Every young person should work with a counsellor to develop a collective project for a sustainable activity that will allow him or her to live while limiting carbon emissions. These experiments could involve companies, to create these alternative spaces, sources of new ideas and new representations.

Inform about the possibility for companies to join the 17,000 companies based in 160 countries that have signed up to the United Nations Global Compact, which is a UN initiative and a call to companies worldwide to align their practices and strategies with 10 principles that derive from the UN's core texts in the areas of human rights, labour, environment and anti-corruption.

The ambition of the Global Compact is to increase the global impact of business by living up to these 10 principles and achieving the 17 DD goals through responsible business and ecosystems that promote change.

Conclusion

Ivan Illitch insisted that the only solution to the ecological crisis was to establish, through a political agreement, a self-limitation. This would allow us to move towards a society that he defines as post-industrial and convivial. He defines the convivial society as a society that gives humans the possibility of exercising the most autonomous and creative action, with the help of tools over which they have control (as opposed to industrial tools that constrain humans), tools that generate meaning in the relations between humans and the world, tools that translate intentionality.

How can we develop this convivial mindset? I have mentioned several avenues, but one particularly important element must also be considered: career counsellors must themselves do this work of reflection and training on transition issues, which now constitute basic knowledge that must be acquired and must be an integral part of the identity of any 21st century citizen.

-

  Acceleration of the implementation of telework (28/30) -Teamwork has become difficult (19 out of 30) -Lack of communication between employees (19 out of 30) -Employees less and less involved in work (15 out of 30) "The human being has become extremely individualistic » "It's an awareness of the importance of things and the relativity of things. Work is important but what is around it is just as important; we also concentrate on the essential values of the family".

  Training focused on adaptation to the workplace after recruitment (23 out of 30); -The training topics are Corporate Social Responsibility issues (psychosocial risks, quality of life at work, equality and discrimination, crisis management) (21 out of 30) and corporate culture (15 out of 30). B/ By developing forward-looking management of jobs and skills -Labour shortage in the industry (20 out of 30) -Employee retention as an important concern (20 out of 30) -Anticipation of skills lost with retirement (13 out of 30) -The change in employees' relationship to work (16 out of 30): imbalance of investment in favour of personal life 3/-Soft skills needs for the future 1. Communication (28 out of 30) 2. Teamwork, collaboration (27 out of 30) 3. "Self-management" (27 out of 30): By the majority: adaptability, commitment, learning, creativity, curiosity, versatility. By half: Corporate culture, Respect, Optimization of the position, Acceptance of constraints, Safety, Responsibility, Management of emotions, Management of conflicts.


Valérie Cohen-Scali

The essence of 'best practice' in career guidance and counselling: Global perspectives, shared realities From school to unemployment: the consequences of the Covid pandemic on emerging adults from disadvantaged backgrounds in France

Introduction

In the newspaper Le Monde of 17 June, 2022, the philosopher Abdennour Bidar was astonished by "the amnesia that has rapidly set in just two years after the ordeal of the COVID-19 pandemic" and called for a major national debate to heal the collective trauma.

The aim of this paper is to identify the consequences of the COVID pandemic on the life paths of young people from disadvantaged backgrounds, who are enrolled in youth career centres for 16-25 year-olds in France and draw some lessons to produce better practices.

The Covid crisis exposed the most fragile people to vulnerability. Vulnerability is a risk of harm, the likelihood of being affected by a threat, and of lacking the necessary protection to cope with it (Castel, 2006).

Our hypothesis was that the pandemic led some young adults, (particularly those from disadvantaged or working-class backgrounds), from social integration to the sphere of vulnerability to the sphere of social disaffiliation as Vincent de Gaulejac had already studied in 1990.

Methodology

Recruitment of participants:

We spent three days in the career services and met young people who had an appointment with their counsellor and who agreed to meet us. We had an office.

The context of Youth Career Centres:

436 career centres are present in France to enable all young people aged 16 to 25 to overcome the difficulties that stand in the way of their professional and social integration. 1.1 million young people are supported each year by these career centres. Nearly 13,600 professionals accompany them in their job or training search. These centres deal with all integration difficulties: employment, training, orientation, mobility, housing, health, access to culture and leisure.

The interviews were recorded, transcribed and processed by thematic content analysis inspired by Hill's (2012) consensual qualitative research. There was a destabilisation of the situation between before and after the pandemic, without any stabilisation. Nothing has happened since school stopped. Vacuity in life, waiting for a job or training. Vague anxiety related to the absence of a rhythm of life, which has not really been found and the absence of clear prospects for a rapid outcome to their situation.

Results

1/ Main difficulties encountered during the pandemic

2/

2/ Erratic action/ endless chaos (N= 7)

Various situations (odd jobs, short training courses) follow one another but without any link between them; young people find themselves tossed about according to opportunities. They have no plans other than to work quickly, caught up in the need to survive.

3/ Rationalised reconversion (N=5)

The initial project was often highly invested. But it was swept away because of the direct or indirect effects of the pandemic (e.g. the impossibility of enrolling in a training course in time) and they had to find a new solution, to reorient themselves in another sector, with varying degrees of difficulty and enthusiasm.

4/ Delayed Project with downgrading (N= 4)

The initial project was not abandoned but lost its initial scope, because often planned training courses were cancelled. These young people have "bounced back" while being in more difficult and less enviable situations than they had originally aspired to.

This pandemic experience has shown its negative and destructive effects on situations by destabilising them profoundly. Such crises cause individuals to enter long transitions with an indeterminate outcome but where it takes time to regain past stability.

5/ Mentioned interventions received

Regarding the intervention they received, the young people mentioned:

-Moral support: counsellors were very available to stay connected with young people, especially during the pandemic, and this was important for young people.

-Material support: financial, but also help with accommodation was needed for young people who had been kicked out of their parental home due to tension and violence.

-Social support: the young people expressed their isolation and the fact that the career centre offered workshops allowing them to get out of their homes and meet each other.

-Psychological support: Many expressed their discomfort or suffering, but few had access to this.

5/-Lessons to be learnt in order to develop best practices to help these young people

In order to develop best practices and to anticipate what to do to protect oneself from the deleterious effects of crises, counsellors should offer more time to reflect on the experience, to learn from it and to develop skills.

For example, it would have been useful to set up reflective workshops after the pandemic so that everyone could reflect on the experience.

It appeared that crisis situations force individuals to implement new skills, for example to follow on-line courses, to develop self-control, the capacity to seek help, to organise themselves in order to maintain a rhythm of life, etc. This reflective time would also have allowed young people to express their emotions and share them.

So, career centres for young people must build spaces for reflexivity about experience and not just places where advice is offered. Very little of this goes on in these centres. Counsellors should not only focus their interventions on the future but they should also help with reflections and analyses on past experiences and associated emotions. This would allow young people to co-construct a new representation of themselves, identify their skills and give meaning to their actions.

In view of the crises that are being predicted, it is urgent that career centres anticipate more appropriate forms of intervention. Best practices must be those that take into account the specific context and must therefore be continuously redesigned.

Thank you for your attention.

Participants

  23 young people aged 18 to 25 enrolled in 2 career centres were interviewed (mean age: 21.8 years, and standard deviation = 2) in the suburbs of Paris: 14 boys and 9 girls. We chose to study their situation one year after the end of the pandemic in 2022.The interview guide was as follows: Starting point: I would like you to tell me what has changed for you since the COVID pandemic? Theme 1: Your educational background Theme 2: Project during the COVID crisis Theme 2: The main difficulties of young people in the post-covid period Theme 3: The needs/expectations of young people in ML today Theme 4: Attitude towards the future Theme 5: Developments in vocational integration support

1. 1

 1 Inability to follow distance learning courses (8 out of 23) 1.2 Confrontation with death and illness (6 out of 23) 1.3 Impossibility of joining a training course (5 out of 23) 1.4. Breach of employment contract or work-study programme due to a drop in activity (

  Future intentions, 2 years after the pandemic 3.1. Don't know what to do (13 out of 23): no plans (8) or unclear plans (5) 3.2 Stay in the same sector of training (5) 3.3 Change direction (5 out of 23) 3/ A typology of post-pandemic courses of action encountered by these young people 1/ Waiting in diffuse anxiety (N=7)


A new model for the prediction of sulfide melt-silicate melt partitioning of chalcophile elements

Ferraina C 1* , Iacono-Marziano G 1 , Gaillard F 1 , Sizaret 1 . 1 ISTO, UMR 7327 CNRS-Université d'Orléans, 1A rue de la Férollerie 45071 Orléans France (*clement.ferraina@cnrs-orleans.fr)

Abstract -Partitioning of chalcophile elements between sulfide and silicate melts is important to understand the formation of magmatic ore deposits and especially metal enrichment in sulfides. Temperature (T), pressure (P), oxygen fugacity (fO2), sulfur fugacity (fS2) and the chemistry of both phases are the parameters which impact this partitioning. New experiments and a large database is used to parameterize the partitioning of chalcophile elements in magmatic systems. This model is essential for the prediction of metal enrichment in sulfides.

I. INTRODUCTION

ARTITIONING OF CHALCOPHILE ELEMENTS between sulfide and silicate melts (D sul/sil ) has been largely investigated, mainly through experiments at mantle conditions and under reduced conditions, i.e. low oxygen fugacities (fO2 < FMQ-1). However, natural magmas show higher oxygen fugacities (< FMQ+2, [START_REF] Gaillard | The redox geodynamics linking basalts and their mantle sources through space and time[END_REF]), and the formation of magmatic sulfide deposits, in crustal conditions, may also occur under higher oxygen fugacities. New experiments and a new model covering this large range of oxygen fugacity are needed. With the oxygen fugacity, other parameters can impact the partitioning of chalcophile elements such as temperature, pressure, sulfur fugacity and composition of the different phases.

II. METHODOLOGY

We performed experiments in internally heated pressure vessels equipped with a rapid quench device at 1200 °C and 700 MPa, under variable fO2 (between FQM-2 and FMQ+2).

The starting material consisted in a volatile-free glass of the Noril'sk-I picrite in addition with 5 wt.% of native S and 2 wt.% of distilled H2O, together placed in Pt-capsules. The specificity of this study is that (i) a metal-undoped composition was used, and (ii) the sulfide melt segregated directly from the silicate melt during the experiment, due to S addition. Magmatic textures were generally preserved owing to the rapid quench.

All samples show equilibrium between a silicate glass, sulfide liquid droplets, olivines and a fluid phase. Silicate and sulfide melts are analyzed for major elements by EMPA (ISTO) and for minor elements by LA-ICP-MS (IRAMAT).

Experimental and literature data were compiled in a thermodynamic model based on exchange reactions. This new model was constructed with different parts.

We first found that the oxygen concentration in sulfide liquid, based on the exchange reaction (1), is critical.

FeS + ½ O2 = FeO + ½ S2 (1)
The O concentration in sulfide liquid is strongly associate with T, P, fO2, fS2 and sulfide composition [START_REF] Kiseeva | The effects of composition and temperature on chalcophile and lithophile element partitioning into magmatic sulphides[END_REF], [START_REF] Fonseca | Oxygen solubility and speciation in sulphide-rich mattes[END_REF].

Secondly, we used experimental data to determine the calculation of Ni and Cu partitioning with variable parameters. These parts are based on exchange reactions (2,3) between sulfide and silicate melts.

NiS + ½ O2 = NiO + ½ S2 (2) Cu2S + ½ O2 = Cu2O + ½ S2 (3)

III. RESULTS & DISCUSSION

1-Oxygen content in sulfide liquid

The oxygen content in sulfide liquid was calibrated using 430 experimental data from variable sulfide liquid compositions: Fe-rich, Ni-rich, and Cu-rich. xFeO in sulfide liquid is calculated using the constant of reaction (1), interaction parameters Wi-j (to consider activity coefficients), fO2 and fS2. Even if the reaction equation ( 1) predict a 0.5 slope with fO2 and fS2, this model seems more accurate with a 0.15 slope. The resulting model is a linear regression considering T, P, fO2, fS2 and the composition of the sulfide liquid. Interaction parameters (Wi-j) in a five-component system for sulfide liquids (FeO, FeS, NiS, Cu2S, Sxs) can be used to calculate the activity coefficients of these species. xFeO in sulfide liquids is positively correlated with P and fO2 and negatively correlated with T and fS2. The quantity of FeO dissolved in sulfide liquid is also dependent of the composition, the more Fe-rich is the sulfide liquid, the more FeO can be dissolved.

2-Partitioning of Ni and Cu

The same treatment is applied to the partitioning of Ni and Cu. Thermodynamic constants of reactions ( 2) and (3) [START_REF] Barin | Thermochemical data of pure substances[END_REF] are calculated together with their dependences on T and P, and the interaction parameters (Wi-j). The interaction parameters used are simultaneously solved with the 'oxygen content' part of the model. Ni and Cu partition coefficients between sulfide and silicate melts are positively correlated with T and fS2, and negatively correlated with P and fO2.

IV. CONCLUSION

New experimental data done in conditions relevant to magmatic sulfides ore deposits are combined with the literature data to create a global model for oxygen content in sulfide liquid and partitioning of chalcophile elements between sulfide and silicate melts. The model allows to predict xFeO in sulfide liquids, DNi sul/sil and DCu sul/sil knowing intensive parameters such as temperature, pressure, oxygen and sulfur fugacities. This model can be used to predict the optimum conditions leading to the formation of maficultramafic magmatic sulfide deposits. P

ACKNOWLEDGMENT

This work has been supported by the French agency for research (ANR project #2010 BLAN62101) and by the Centre-Val-de-Loire Region. The authors thank Ida di Carlo for the in EMPA sessions and the IRAMAT for the LA-ICP-MS sessions.


Mathieu Kermarec

Louis Bigo
email: louis.bigo@univ-lille.fr

Mikaela Keller
email: mikaela.keller@univ-lille.fr

Late-Breaking / Demo

Training sequence models such as transformers with symbolic music requires a representation of music as sequences of atomic elements called tokens. State-of-the-art music tokenizations encode pitch values explicitly, which complicates the ability of a machine learning model to generalize musical knowledge at different keys. We propose tracks for a tokenization encoding pitch intervals rather than pitch values, resulting in transposition invariant representations. The musical expressiveness of this new tokenization is evaluated through two MIR classification tasks: composer classification and end of phrase detection. We release publicly the code produced in this research 1 .

INTRODUCTION AND RELATED WORKS

Machine learning, and in particular deep learning, has become a dominant approach to a variety of symbolic MIR tasks including content analysis, classification and generation due to the increasing availability of large corpora and sophisticated neural architectures [START_REF] Briot | Deep learning techniques for music generation-a survey[END_REF][START_REF] Herremans | A functional taxonomy of music generation systems[END_REF]. A number of Natural Language Processing (NLP) techniques have been twisted for the modelling of music including the selfattention mechanism [START_REF] Huang | Music transformer: Generating music with long-term structure[END_REF][START_REF] Keller | What musical knowledge does self-attention learn?[END_REF][START_REF] Jiang | Discovering music relations with sequential attention[END_REF], transfer learning [START_REF] Wang | Musebert: Pre-training of music representation for music understanding and controllable generation[END_REF], or context vectors [START_REF] Chuan | From context to concept: exploring semantic relationships in music with word2vec[END_REF]. This practice is generally justified by the common assimilation of music to a kind of language (the language of music) [START_REF] Cooke | The language of music[END_REF][START_REF] Jackendoff | Parallels and nonparallels between language and music[END_REF], as well as the temporal nature of music which promotes its representation as a sequence of elements, for instance musical notes, that can be processed in a way similar to sequences of words.

NLP challenges have motivated the design of sophisticated neural network architectures, such as LSTM and Transformers, dedicated to the modelling of sequences with long-term relationships between their elements. These elements, called tokens, generally correspond to successive words in text. Beyond their use in NLP, these models have successfully shown some ability to model sequences of other type of data including musical content [START_REF] Huang | Music transformer: Generating music with long-term structure[END_REF]. Representing music as sequences of tokens is however complicated as the organization of elements in the score feature possible simultaneity and overlapping as well as strict timing constraints that are absent from text.

Existing strategies to encode symbolic music into token sequences include the Midi Like tokenization [START_REF] Oore | This time with feeling: Learning expressive musical performance[END_REF] inspired by the syntax of MIDI messages and the REMI tokenization [START_REF] Huang | Pop music transformer: Beat-based modeling and generation of expressive pop piano compositions[END_REF] that more closely sticks to the musical score by introducing duration and position tokens. In a more recent tokenization, tokens that define a musical event together are grouped as compound words [START_REF] Hsiao | Compound word transformer: Learning to compose full-song music over dynamic directed hypergraphs[END_REF]. In order to facilitate the comparison of major tokenizations in MIR research, the MidiTok python library [START_REF] Fradet | MidiTok: A Python Package for MIDI File Tokenization[END_REF] enables the direct translation of any MIDI content into most common tokenizations.

Common tokenizations encode pitch information explicitly, for example with tokens such as pitch:C3, which are afterward fed to a sequence model. This contrasts however with a tendency of human listeners to perceive and memorize musical sequences in terms of relative pitches. This limitation arguably complicates the ability of such models to exploit learned musical knowledge across the different keys. This problem is generally tackled by a data-augmentation procedure that consists in transposing the training data in the twelve keys, which dramatically increases the resources required to train the model. As an alternative, we argue for a token representation encoding pitch intervals and therefore invariable to transposition, that would facilitate the uniform transposition of musical knowledge learned by sequence models at any key without any resort to data augmentation.

TRANSPOSITION INVARIANT TOKENIZATION

Note features (position, duration and pitch) are grouped in the REMI representation as successive tokens. Starting from this representation, the uniform pitch-interval tokenization removes pitch tokens and add pitch interval tokens in between groups of tokens defining a musical note together. Pitch interval tokens represent the semi-tone distance between the two surrounding notes, whether they are played successively or simultaneously. In contrast, the spatial pitch-interval tokenization distinguishes pitch in-

EVALUATION EXPERIMENTS

Experimental setting

As an exploratory experiment to study and compare the expressiveness of different tokenizations, we represent each music sequence as a bag-of-tokens with TF-IDF weights 2 . Importantly, this representation ignores how the tokens follow one another, resulting in the loss of an essential part of musical information. We argue that this challenging abstraction is a reliable way to highlight the expressiveness of our proposed tokenizations. We deliberately limit our experiments to the use of a logistic regression model in order to facilitate the interpretation of the results and the comparison of the impact of the different tokenizations.

Classifications Tasks

For the composer classification tasks, we use the GiantMIDI-Piano dataset [START_REF] Kong | Giantmidipiano: A large-scale MIDI dataset for classical piano music[END_REF] from which we extracted a total of 740 pieces from 6 composers: Bach, Mozart, Beethoven, Chopin, Schubert and Liszt. Each composer subset is split into a train set and a test set, from which 2000 excerpts of 60 seconds were randomly sampled and tokenized using MidiTok [START_REF] Fradet | MidiTok: A Python Package for MIDI File Tokenization[END_REF] with pitch interval tokenizations plus a baseline REMI pitch mute tokenization which 2 term frequency-inverse document frequency : counting the number of occurrences of each token in the sequence and scaling the count by the frequency of the token in the corpus.

is equivalent to REMI but with all pitch tokens replaced by a same token regardless of their pitch value. The TAVERN dataset [START_REF] Devaney | Theme and variation encodings with roman numerals (tavern): A new data set for symbolic music analysis[END_REF] was used for phrase end detection. It includes 27 pieces by Mozart and Beethoven, with phrase boundary annotations resulting in 1060 musical phrases. The dataset is split into a train set and a test set, conserving the original proportion of each composer.

The training set was reduced to 1600 chunks of two consecutive bars that were randomly sampled with a balanced representation of chunks including an end of phrase. The test set was similarly reduced into 1100 chunks.

Figure 2 shows that the tasks vary in difficulty and that the choice of tokenization can have dramatic impacts on the performance of the classifiers. In particular, Compound Word tokenization seems poorly suitable for the framework of these experiments, likely because of the high dimensionality induced by its vocabulary of tokens (see Table 1) as compared to the moderate number of training examples. REMI and the Pitch Interval tokenizations have similar performances for composer classification, except for the Schubert vs. Chopin task in which PI tokenizations perform better. We hypothesize that the performance of REMI for the two other classifications is partly due to the pitch range difference between the repertoires of the composers, Liszt and Beethoven arguably employing larger pitch ranges than Bach and Mozart, which is by nature better encoded by absolute pitch tokens. Finally, we see a significative outperformance of the SPI tokenization for the end of phrase detection, presuming a promising ability of this representation to model abstract musical knowledge.

CONCLUSIONS AND PERSPECTIVES

We showed that the representation space induced by the choice of a tokenization, for a specific MIR task, can have a strong impact on performance and that transposition invariant tokenizations can improve the musical expressiveness of this space. Future works include extending the comparison of these tokenizations through generative tasks involving the training of a transformer model. We also plan to experiment with other variations of these tokenizations to improve further their musical expressiveness. This includes the encoding of horizontal pitch intervals between the lowest notes of the score, instead of the highest notes, which is expected to improve the modelling of structural features including the detection of end of phrases.

  tervals between simultaneous and consecutive notes, respectively with horizontal (HPI) and vertical (VPI) pitch interval tokens. In addition, notes occurring at the same onset are systematically ordered in the token sequence by decreasing pitch. Therefore, VPI are exclusively negative values and HPI mostly link high notes which presumably encourages the modelling of melodic features. These two tokenization are illustrated on Figure1.

Figure 1 .

 1 Figure 1. Three tokenizations of a musical sequence. The dotted frames group tokens describing a same note.

Figure 2 .

 2 Figure 2. Composer classification and end of phrase detection performed by a logistic regression on TF-IDF token representations, with 5 different tokenizations.

Table 1 .

 1 Vocabulary sizes of the tokens extracted from several datasets tokenized using REMI or Compound word(CPW). The values for transposition invariant tokenizations are close to those of REMI

		Bach+Liszt Mozart+Beethoven Chopin+Schubert TAVERN
	REMI	211	207	210	136
	CPW	78k	49k	59k	771

https://github.com/MathieuKermarec/improving-tokenizationexpressiveness-with-pitch-intervals

ACKNOWLEDGMENTS

The authors are grateful to the Algomus and Magnet teams for fruitful discussions. This work is supported by a special interdisciplinary funding (AIT) from the CRIStAL laboratory and the Merlion PHC Music Language Processing N°4 8304SM funded by Campus France.


Andrea B Taylor

Clément Zanolli

Editorial announcement

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

At the end of 2019, J. Michael Plavcan stepped down as the Editor of the Journal of Human Evolution (JHE) and passed on his responsibilities to Andrea B. Taylor. At the end of 2020, David M. Alba stepped down as the Editor and passed on his responsibilities to Clément Zanolli. Mike served the JHE from 2015 to 2019, and David from 2017 to 2020. We can only skim the surface of their impact on and contributions to the JHE. Over the course of their tenure, Mike and David handled upward of 1300 submissions. With the dedicated editor position for special issues ending in 2018 (held at that time by Sarah Elton), they also took over special issues as part of their editorial responsibilities, managing five special issues between them. Under their stewardship, the JHE impact factor rose from 3.155 in 2018 to 3.534 in 2019 and to 3.895 in 2020. That they accomplished all of this during a time of tremendous flux in journal publisher leadership cannot be overemphasizedfour journal publishers in five years. Due in no small part to their efforts, we inherited a journal that remains strong and well positioned to continue as the leading journal in paleoanthropology. As with all previous editors for the JHE, emeritus Editors Mike and David continue to serve as active Associate Editors for the Journal. On behalf of the JHE and its readership, we offer our sincere gratitude for all they have done for the journal and the field.