Roxanne Tsang
email: roxanne.tsang@griffithuni.edu.au

Liam M Brady
email: liam.brady@flinders.edu.au

Sebastien Katuk

Paul S C Taçon
email: p.tacon@griffith.edu.au

Francois-Xavier Ricaut
email: francois-xavier.ricaut@univ-tlse3.fr

Dr Matthew G Leavesley
email: matthew.leavesley@gmail.com

EAST SEPIK, PAPUA NEW GUINEA Karawari-Arafundi Region

François-Xavier Ricaut

Prof M Liam

Brady

Prof S C Paul

Taçon

Dr François-Xavier Ricaut

Agency, affect and archaeologist: transforming place with rock art in Auwim, upper Karawari Arafundi Region, East Sepik, Papua New Guinea

Keywords:

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Introduction

Rock art has been reported from across Papua New Guinea (PNG) for over a century. The first published account came from [START_REF] Seligmann | The Melanesians of British New Guinea[END_REF], who noted incised designs on Goodenough Island in Milne Bay Province at the south-eastern tip of the country. Seligmann's observation was followed by others such as [START_REF] Strong | Rock paintings from Central District, Papua (British New Guinea)[END_REF][START_REF] Strong | More rock paintings from Papua[END_REF], who noted paintings from the Central Province. [START_REF] Williams | Papuan petrographs[END_REF] undertook the first analysis of PNG rock art, a comparative stylistic analysis between rock art from the Central and Milne Bay Provinces, and ultimately concluded motifs were created simply as 'art for art's sake'. From the 1940s onwards, references continue to appear from locales spread across mainland and island PNG, with the majority providing descriptions of site type (rockshelter, boulders), techniques used to create motifs (painting, engraving, charcoal drawing, and a rare instance of finger fluting [Ballard 1992a]), motif styles (e.g. scroll-like designs, animals such as lizards, anthropomorphs, material culture objects, mythical figures and various geometric shapes) and on occasion the contexts in which they occur such as at burial sites, and the geological substrate (e.g. [START_REF] Edwards | Preliminary report of the Cruz Mayor Rock Art Expedition to Papua New Guinea[END_REF][START_REF] Egloff | The rock carvings and stone groups of Goodenough Bay, Papua[END_REF][START_REF] Gabriel | The 'Karawari Caves Precinct' of the Sepik River Basin, Papua New Guinea[END_REF][START_REF] Gorecki | Rock art in the Wahgi-Jimi region[END_REF][START_REF] Gunn | Rock Art on Tabar, New Ireland Province, Papua New Guinea[END_REF][START_REF] Leask | Rock engravings and paintings of the Sogeri District of Papua[END_REF][START_REF] Peterson | A note on two archaeological sites in New Ireland[END_REF][START_REF] Pretty | Preliminary catalogue archaeological monuments in Territory of Papua New Guinea[END_REF][START_REF] Specht | Rock art in the western Pacific[END_REF][START_REF] Wilson | Picturing Pacific prehistory: the rock art of Vanuatu in a western Pacific context[END_REF][START_REF] White | Ol Tumbuna: archaeological excavations in the eastern Central Highlands, Papua New Guinea[END_REF]. Perhaps the most detailed study of PNG rock art comes from Byrne's research into the rich assemblage of engravings (cupules, rectilinear and curvilinear motifs, and three-dimensional or sculpted boulders) on Uneapa Island (New Britain). Her research focused on investigating the social and temporal contexts of engravings by exploring the distributional patterning, cultural associations, landscape locations, and their physical properties, and concluding that the island's rock art had complex social relations that governed its 'production and consumption through time' (Byrne 2013: 75). PNG's rock art has also featured in broader, panregional studies exploring patterning in Austronesian painting and engraving traditions from the western Pacific region (e.g. [START_REF] Specht | Rock art in the western Pacific[END_REF]Ballard 1992b;[START_REF] Wilson | Rock art of the Pacific: context and intertextuality[END_REF].

While there is unlikely one definitive reason for researchers not undertaking detailed surveys or analyses of PNG rock art (e.g. more interest in PNG's role in Pleistocene colonisation studies or logistical challenges with accessing rock art sites which are located mainly in remote, mountainous regions), this paper reveals there is considerable potential for PNG rock art research, especially in terms of exploring people's contemporary relationships with their rock art.

For decades, archaeologists and anthropologists (among others) have sought to capture the meaning and interpretations of rock art from Indigenous people. However, more recently, there has been an increasing interest in moving beyond simply recording what a motif is or represents, to instead exploring meaning, symbolism, and significance of rock art in contemporary settings by focusing on the myriad social and cultural contexts considered appropriate at the time of an individual's engagement with, or interpretation of, motifs and sites. Some of the key themes to emerge from these studies include the role rock art plays in reaffirming or reinforcing identity, the relational (e.g. kinship) and affective (emotional) contexts people use to show how images are made meaningful, motifs as inspiration for contemporary artworks, and how motif interpretations can be multivocal depending on multiple factors such as health and wellbeing, an individual's position in society, and historical circumstances (e.g. papers in Brady and Taçon 2016; see also, e.g. Brady et al. 2016[START_REF] Brady | What painting? Encountering and interpreting the archaeological record in western Arnhem Land, northern Australia[END_REF][START_REF] Colwell-Chanthaphonh | Memory pieces and footprints: multivocality and the meanings of ancient times and ancestral places among the Zuni and Hopi[END_REF][START_REF] Goldhahn | I have done hundreds of rock paintings': on the ongoing rock art tradition among Samburu, northern Kenya[END_REF][START_REF] Merlan | The interpretative framework of Wardaman rock art[END_REF][START_REF] Taçon | Eagle's Reach: a focal point for past and present social identity within the northern Blue Mountains World Heritage area, New South Wales, Australia[END_REF][START_REF] Young | Signs from the ancestors: Zuni cultural symbolism and perceptions of rock art[END_REF]). This paper builds on these studies by presenting details from a new rock art recording project in the East Sepik province of northern PNG. We begin by providing an overview of rock art from the Upper Karawari-Arafundi region, and second, presenting a case study about the production of rock art stencils at the Apuranga site in 2018 in Auwim traditional territory. Our primary interest is exploring the network of relations that these creative acts were embedded in, the agency of artists, affective responses of Auwim individuals, and in particular, the presence of an archaeological team. Drawing on frameworks of agency and affect in visual arts, we present a narrative to understand the context in which the Apuranga rockshelter, once devoid of rock art, was transformed into a rock art site with the creation of stencils. By doing so, we are exploring the reasons or motivations behind the rock art production as well as the potential implications of researcher presence in this process.

Auwim, Upper Karawari-Arafundi region

Before European arrival, the Auwim were a semi-nomadic people residing in the rugged limestone mountains and gorges of the Upper Karawari-Arafundi region, south of the Sepik River (Fig. 1). The Auwim also practised a hunter-gatherer lifestyle, a rare occurrence for tropical forest people in eastern PNG (Roscoe and Telban 2004: 94). Around the 1950s, the Auwim moved from their high-altitude location to the lowland wetland altitudes to present-day Auwim village, ostensibly to seek basic government services. Auwim village (Fig. 2) is surrounded by tropical rainforest vegetation and sago swamps which grow abundantly in the region [START_REF] Edwards | Preliminary report of the Cruz Mayor Rock Art Expedition to Papua New Guinea[END_REF][START_REF] Roscoe | The people of the lower Arafundi: tropical foragers of the New Guinea rainforest[END_REF]. In 2018, Auwim village consisted of 29 households. The population has grown from 41 in 1957 to around 300 in 2018 [START_REF] Bartole | Giving (up) a traditional problem-solving ritual: materialisation of power and self-transformation amongst the people of Awim, East Sepik Province[END_REF]Roscoe and Telban 2004: 114;[START_REF] Sullivan | Sago bark painting and the transformation of community identity on the Arafundi River[END_REF][START_REF] Tsang | Arafundi, East Sepik Province, Papua New Guinea[END_REF]. Auwim belong to one of two major original clans -Wandukumbay and Mungkumbay -and are then divided into 20 sub-clans. Today, the Auwim speak the local language, Tapei (or Tape), and the PNG lingua-franca, Tok Pisin, which has been widely spoken since the 1960s (for further details of Auwim social and cultural life see, e.g. [START_REF] Edwards | Preliminary report of the Cruz Mayor Rock Art Expedition to Papua New Guinea[END_REF][START_REF] Roscoe | The people of the lower Arafundi: tropical foragers of the New Guinea rainforest[END_REF]. Figure 1. Map showing the case study area location, Auwim, East Sepik, Papua New Guinea, including other sites mentioned in the text (produced by Andrea Jalandoni; base map by ESRI National Geographic). Figure 2. Auwim village in 2018 (photo: William Pleiber, Papuan Past Project).

Contact with, and exposure to, Europeans (in the first instance, Germans) in the broader Upper Karawari-Arafundi (also referred to as Lower Arafundi) began in the early 1900s and is characterised by relatively fleeting interactions. Stories from the Imanmeri (a neighbouring language group) tell of a German expedition in 1912 traversing the region and taking some people captive (Roscoe and Telban 2004: 97). In 1928, gold prospectors travelled across the region, followed by various government patrols (Gorecki and Jones 1987a;Roscoe and Telban 2004: 98). During the Second World War, Australian and Japanese militaries travelled through the area (Roscoe and Telban 2004: 98). While missionaries began arriving in the East Sepik region in the 1930s, it was not until the late 1950s that they began interacting with the Auwim, where they issued 'edicts against the male spirit cult and burning sacra from their men's house' (Roscoe and Telban 2004: 98). From the 1960s, European contact with Auwim became more sustained and led to the appointments of village officials (or luluais), censuring of the population, and timber becoming a source of income (Roscoe and Telban 2004: 98).

Historical, ethnographic and archaeological research in the East Sepik region

The earliest available sources concerning Auwim and cultural practices come from administrative government patrols, explorers along the Sepik River, and labour recruiters (Roscoe and Telban 2004: 93-94). Scholarly research in the Upper Karawari-Arafundi region began in the late 1950s and mainly focused on its artistic traditions, particularly its elaborately carved objects. In 1958, anthropologist Anthony Forge visited the Abelam (approximately 140 km north of Auwim) to 'purchase artefacts for a museum' and collected information on social organisation, aesthetics, religion, and ritual life (Forge 1959a(Forge , 1959b;;cited in Gabriel and Gorecki 2014: 6). He was followed by Alfred Bühler, who produced a description of cult crocodile figures from Karawari (also spelt Korewori) [START_REF] Bühler | Kultkrokodile vom Korewori[END_REF]. A few years later, Eike Haberland collected and recorded hooked figures including sago-bark paintings from the 'Auwim, Warlamas (or Kopokmeri), Imanmeri, Yamandim, and Imboin in 1961and 1963[START_REF] Haberland | Zum Problem der 'Hakenfiguren' der südlichen Sepik-Region in Neuguinea[END_REF], 1966[START_REF] Haberland | The caves of Karawari. D'Arcy Galleries[END_REF]cited in Gabriel and Gorecki 2014: 39; see also Roscoe and Telban 2004: 96). Haberland also worked alongside Siegfried Seyfarth in 1974, exploring the region's ethnology [START_REF] Haberland | Die Yimar am oberen Korewori (Neuguinea)[END_REF]. In the early 1970s, Christian [START_REF] Kaufmann | Ethnographische Notizen zur Basler Korewori-Sammlung: aus den Ergebnissen der Sepik-Expedition 1972-3[END_REF][START_REF] Kaufmann | Korewori: magic art from the rainforest[END_REF] researched sculptures and figurative art from the region. In 1991, anthropologist Borut Telban began the only long-term ethnographic fieldwork in the region with Karawari-speaking people focusing on cosmology, social organisation, ritual and death [START_REF] Telban | Dancing through time: a Sepik cosmology[END_REF]Roscoe and Telban 2004: 99) while his student, Tomi Bartole, explored the relationships between materialising power and self-transformation, a contemporary ritual practice among the Auwim [START_REF] Bartole | Giving (up) a traditional problem-solving ritual: materialisation of power and self-transformation amongst the people of Awim, East Sepik Province[END_REF]). Telban's contribution to ethnographic studies in the region also included a summary of Auwim ethnography from unpublished patrol reports [START_REF] Roscoe | The people of the lower Arafundi: tropical foragers of the New Guinea rainforest[END_REF]. In 2005, anthropologist Nancy Sullivan began researching rock art and other decorative arts practices such as sago and paperbark paintings (see below). Archaeologically, excavations undertaken in the East Sepik region have revealed Pleistocene occupation. In 1987, Gorecki excavated the Kowekau rockshelter, obtaining a date of 14 000 BP (Gorecki et al. 1987;[START_REF] Yen | Environment, agriculture, and the colonisation of the Pacific[END_REF]). Gorecki and Jones surveyed the region's rock art in 1987 (see below) but did not excavate any sites. A recent excavation at Paimbunkanja rockshelter (approximately 81 km south of Auwim village) by the 'Papuan Past: archaeology and genetics in Papua New Guinea' (see below) revealed a late Holocene period of occupation between 2000-3000 years BP as represented by knapped stone artefacts made from locally sourced pebble [START_REF] Tsang R | Rock art and long-distance prehistoric exchange behaviour: a case study from Auwim, East Sepik, Papua New Guinea[END_REF].

Rock art of the Upper Karawari-Arafundi region

The earliest known report of rock art from the Upper Karawari-Arafundi region is by Gorecki andJones (1987a, 1987b) during their survey of the region to identify rockshelters with the potential to excavate for evidence of early human occupation. While their report indicated the geology of rockshelters did not appear conducive for early human occupation, they noted many sites were decorated with rock art that they remarked was associated with religious and other customary activities (Gorecki and Jones 1987a: 2). Gorecki and Jones referred to 20 rock art sites in 1987; however, only 10 -Amboye (or Amboise), Kalapul, Kandamati, Limbut, Paigun, Pundimbung, Timblari, Wagum, Wangelia and Yanbimban -were visited and recorded during their fieldwork in the area (Gorecki and Jones 1987a: 10-11;1987b: 10;Gabriel and Gorecki 2014: 12). The other ten sites (Imboin, Mambanekandja, Massendenai obelisks, Mendal, Nadim, Ombremas Standing Stones, Pukan, Yembinambasekim, Yuan and Yuminim) were only mentioned to them by local informants noting that they also contain rock art. Of these, only Pukan, Pundimbung and Yembinambasekim are located in Auwim territory, with new paintings recorded being produced at Pundimbung in 1987 (Gabriel and Gorecki 2014: 12) (Table 1). They noted that the assemblage consisted of stencils and paintings created using red, yellow and white pigments (Gorecki and Jones 1987b). Stencil motifs consisted of hands, hands + wrist + forearm, feet, finger 'messages', shell ornaments (e.g. kina [large, crescent-shaped usually made from gold-lip and hung around the neck], rings, nose-pegs, and belts or ropes), animal body parts (e.g. cassowary leg, megapode foot, dog paws and legs), and objects such as bone daggers, bone spoons, flying fox needles, turtle bones, bilum (bag made from natural fibre), leaves, metal bush knives, and other unknown objects (Gorecki and Jones 1987a: 10). Paintings were classified by subject matter and style and consisted of hands, kina shell, cassowary tracks, complex figures, geometric figures, radiating and parallel lines, crosses, circles, chevrons and 'stains' (likely indeterminate motifs) (Gorecki and Jones 1987a: 11, b: 10). They also commented that the style of motifs here was different to those encountered in the highlands region (dominated by curvilinear motifs), as well as highlighting the local significance of these sites with rock art, noting, 1) their association with their dead, 2) initiation of young men, and 3) a symbolic expression of how they relate to place and landscape through origin narratives associated with specific rockshelters or sites [START_REF] Gabriel | The 'Karawari Caves Precinct' of the Sepik River Basin, Papua New Guinea[END_REF]. Furthermore, they emphasised the continuity of the artwork given that local informants were able to identify creators of hand stencils in 1987 (Gorecki andJones 1987a, 1987b). Although no attempts have been made to directly date the art, superimpositions, exfoliated surfaces and repainting on hollowed surfaces offers potential for future work.

Site In their 2004 overview of the people and culture of the Upper Karawari-Arafundi region, Roscoe and Telban (2004: 94) make a brief remark about rock art that draws attention to the ritual significance of rock art sites. They note that people here were 'progenitors of an important rock art tradition that used caves as cult structures functionally equivalent to men's houses, pointing to an important analogical transformation of ritual culture'.

Following Gorecki and Jones' work, Nancy Sullivan led a research team in the Upper Karawari-Arafundi region between 2005-2008 and produced an unpublished report where it was stated they had visited 200 previously unknown rock art sites. However, only 70 appear to have been systematically recorded, and only eight are described in any detail in their report. 1 [START_REF] Edwards | Preliminary report of the Cruz Mayor Rock Art Expedition to Papua New Guinea[END_REF]. Of the eight sites they described, three are in Auwim territory: Pundimbung (also spelt Bundingbum in their report), Aekinyam (this site is likely the same site recorded in 2018 by Tsang as Akuansam [START_REF] Tsang | Arafundi, East Sepik Province, Papua New Guinea[END_REF]]), and Kundumbue (also Kundumbu), while the territorial affiliation of the remaining five has yet to be verified but given one of Sullivan's two research bases was at Auwim, it is likely they are also in Auwim territory (Table 1). Analysis of the eight sites they reported indicates that site dimensions range between 2-6 m in width and 16-75 m in length, and sites are typically located more than a one-hour walk from the present-day Auwim village. The sites are difficult to access because they are primarily located on cliffs or vertical rock faces where certain sites (e.g. Aekinyam, Takinyaekanga, Kundumbue) require additional climbing equipment to access the decorated rock surfaces (Fig. 3a,3b). Edwards and Sullivan (2008) also emphasised the rich ethnographic record associated with the region's rock art. For example, they described how some decorated rockshelters could be linked to warfare represented as trophies placed at some rockshelters (e.g. skulls painted with red ochre belonging to esteemed warriors). There also was an association with death through human bones stored in rockshelters. Origin theories are associated with various spirits, as is male initiation related to the creation of hand stencils and handprints. Moreover, they described that decorated rockshelters are used for seasonal occupational sites for both domestic and ritual activities (e.g. spaces for male initiation, cooking and sleeping) (see more details in Edwards and Sullivan 2008: 16-23). The available link between ethnographic data with the artwork itself suggested the potential for more focused research.

Other details in their report include descriptions of surface materials observed in 2008, including human skeletal remains, animal bones (e.g. pig skulls, flying fox bones, other marsupial skulls), material culture objects such as weathered bamboo flutes, clay pots, remains of bilums, other burial or grave goods, and fireplaces (Edwards and Sullivan 2008: 24-27). These materials suggest the rockshelters they visited were likely used for some time.

Most recently, [START_REF] Tsang R | Rock art and long-distance prehistoric exchange behaviour: a case study from Auwim, East Sepik, Papua New Guinea[END_REF] undertook the first detailed analysis of Auwim rock art, focusing on distinctive kina stencils. Auwim ethnographic knowledge about kina stencils made at Auwim rockshelters was used to demonstrate the ongoing cultural significance of kina, and at the same time, their role as symbolic reminders of the importance of 'prehistoric trade networks' linking the Torres Strait islands (north-eastern Australia) and PNG.

While in-depth rock art research into Auwim and the broader Upper Karawari-Arafundi region is still in its infancy, this previous research reveals considerable potential for further research in the area. In particular, the role of ethnography and contemporary narratives about people's relationships to Auwim rock art offers a useful avenue to explore the cultural significance of motifs, especially those created in the very recent past.

'Papuan Past' project and rock art context

Since 2016, the 'Papuan Past' project has been exploring the modalities of human population settlement and adaptation, that is, biological, cultural and technical evolution, over the last 50 000 years in the broader New Guinea region with a particular emphasis on the lowland area of the Upper Karawari River, and the highlands regions (Chimbu, Jiwaka, and the Western Highlands provinces) (see, e.g. [START_REF] Tsang R | Rock art and long-distance prehistoric exchange behaviour: a case study from Auwim, East Sepik, Papua New Guinea[END_REF][START_REF] Pedro | Papuan mitochondrial genomes and the settlement of Sahul[END_REF]. The broader archaeological investigation in the Upper Karawari-Arafundi region led to opportunities in May-June 2018 to visit rock art sites within Auwim traditional borders and resulted in the development of RT's PhD research.

Upon arriving at Auwim village, the research team (RT, SK, F-XR, MGL) discussed with the Auwim community the project, aims, methods and recruitment of Auwim community members to assist with the excavation, genetic and rock art research program. After securing permission to undertake our research, we trekked to a base camp at Angarik (also spelt Ang-garik or Angalip) and spent four days visiting and recording four of the previously noted rock art sites in Auwim territory -Akuansam, Pukan, Pundimbung and Kundumbue. Afterwards, we visited a nearby village before spending five days carrying out an excavation at Paimbunkanja rockshelter and conducting interviews with Auwim community members about rock art, collecting saliva samples for genetic study, and recording genealogies of Auwim community members.

Upon returning to Auwim village at the conclusion of the excavation, we were told by Auwim community members that we 'ought to visit another rock art site' of which they knew. The following day we trekked to a site known locally as Apuranga, where we encountered motifs that were bright and fresh-looking in appearance (Figs 4 and5). Upon arriving at the site, the Auwim villagers accompanying the team revealed the stencils were 'created last week', that is, when the research team were away from Auwim village, visiting Akuansam, Pundimbung, Pukan and Kundumbue, excavating Paimbunkanja, and carrying out interviews. They also stated that no rock art had been here before the production of this recent painting and stencilling event. (a, c, e andg) before enhancement: a hand/palm, a thumb and finger stencils; hand + arm and hand + forearm stencil; foot and toes stencils; and bone stencil respectively with the appearance of one-week-old. Right down (b, d, f and h) after picture enhancement using DStretch (lbl, labi, crgb and ywe colour filters, respectively) shows no older art (original photos: William Pleiber, Papuan Past Project).

Apuranga rock art site

Apuranga is situated on a limestone cliff face overlooking Auwim village (Figs 6 and 7) in the territory of the Apem and Wakam sub-clans. The rockshelter is approximately 60 m long and 6 m deep. In addition to the rock art, only human skeletal remains (skulls, long bones) were found here and relate to the narrative provided below. The rock art was concentrated at the entrance, middle and end of the rock face of the shelter. The entire decorated rockshelter was systematically photographed at the individual motif and panel level, and a narrative from Auwim villagers about the production of stencils was recorded (see below).

In the first instance, motifs were digitally enhanced using DStretch (Version 8.3). No evidence of superimposition was identified. Some variations in appearance -brighter/fresher v. slightly faded -were observed, suggesting that rock art production could have occurred in multiple episodes (Figs 4 and5). Following [START_REF] Brady | Pictures, patterns, and objects: rock-art from the Torres Strait Islands, northeastern Australia[END_REF], recorded motifs were classified into a 4-level hierarchical scheme to explore the stylistic variation in the assemblage2 (see Table 2, Fig. 8). A total of 77 motifs were identified, indicating a large number of motifs were created during a short period of time. Of these, three are indeterminate, and 74 are determinate (Fig. 9). Of the 74 determinate motifs, figurative motifs account for 91% (n=67) of the assemblage, with non-figurative motifs accounting for only 9% (n=7) of the site's rock art. Human appendages (hand + wrist + forearm, hand, fingers, feet, long/tibiotarsus bone) dominate the assemblage (n=65, 98%).

Level 1:

Indeterminate Determinate

Level 2: Non-figurative Figurative

Level 3: Non-figurative group motif forms: geometric shape Figurative group motif forms: plants, human appendages and material culture.

Level 4: Specific motif forms. These consist of a specific identification for individual motifsfor example, geometric shape (e.g. circleshape).

Specific motif forms. These consist of a specific identification for individual motifs. For example, plants (e.g. leaf), human appendages (e.g. hand + wrist + forearm, hand, fingers, and foot), and material culture (e.g. crescent-shaped object [kina?]).

Level 4a:

More specific motif forms. These consist of a sub-specific classification for specific motif forms (e.g. under hand + wrist + forearm is left hand + wrist + forearm, or right and left hands, 2fingers, 3-fingers and right or left foot).

Table 2. Classification of rock art imageries from Apuranga following Brady (2010).

Apuranga contains only stencilled motifs, with Auwim community members stating that ochre can be found along creek banks on the way to the site. Motifs were created by placing large amounts of ochre onto the palm, chewed (in a similar way to chewing betel nut from the Areca palm) but using only incisors, then mixed in the mouth with saliva and sprayed over the object or appendage, leaving the negative stencil on the rock wall. Auwim community members informed the research team that water or other binders were not used to form the pigment mixture [START_REF] Tsang | Arafundi, East Sepik Province, Papua New Guinea[END_REF]. A freshly chewed betel nut shell was also recorded on the floor of the rockshelter directly underneath a panel of stencils.

The individual artists' names were not collected at the time of our visit; however, it was stated by Auwim community leader, SK and other Auwim who accompanied the team to the site that the rock art was created by their clan members one week before visiting. Owing to differences in the appearance of motifs -some already deteriorating and fading, others fresh with slightly wet paint present -we suggest that motifs were created over multiple visits during the week before our visit. Information about specific motifs or relationships to the site's narrative (see below) were not collected at the time of the interview, nor did SK and other Auwim accompanying the research team mention anything about specific motifs that were made. Figure 8. Classification of rock art motifs at Apuranga (following [START_REF] Brady | Painting patterns: Torres Strait region rock-art[END_REF][START_REF] Brady | Pictures, patterns, and objects: rock-art from the Torres Strait Islands, northeastern Australia[END_REF].

'Dwarfs' or bush spirits and fear

During the site visit, RT conducted an interview with SK about stories related to the site and its new rock art in the Melanesian pidgin language, Tok Pisin, a language RT is fluent in (Fig. 9). The written version of the narrative was later read to SK and other Auwim members for accuracy and approved. The story reveals that Apuranga is associated with an ancestral narrative about 'dwarfs' (bush spirits or non-spiritual beings), ancestral spirits and massacres (as reported in Tsang 2018: 13-14): Apart from the newly made hand stencils, previously, there were human skeletons in Apuranga rockshelter. No one visits this shelter because prehistorically, there were dwarfs that live there but in an underground house beneath the rockshelter. These dwarfs murdered villagers when they went out to extract sago or hunting. They leave the skulls in the rockshelter, perhaps as trophies. Other villagers kept wondering why some of them were missing and after some time, had a search party out. When they arrived at Apuranga, they saw numerous skulls laid out. They knew something exists beyond this cave. One day they saw the cave-hole, tried digging it out but never succeeded. All gathered for a meeting and agreed to spiritually wake one of their spirit ancestors to assist them. The creek nearby swelled and magically flowed into the rockshelter and the hole underground. This allowed the ancestral magician into the dwarf's shelter and killed all of them, including their chief. After that, no more villagers were missing but the cave was still left unused. SK ended the story by explaining that with the presence of researchers in the village who expressed an interest in rock art, some clan members had gone and painted their 'hand marks' on the rockshelter walls making it available to be used again for the community. These motifs were made before the community invited the research team to visit the site.

Discussion

Several strands of this narrative can be woven together to generate insight into the Auwim's contemporary relationship to the site, its motifs, and its affective and relational dimensions. First, the narrative describes how Auwim feared 'dwarfs', and by extension, the place where they resided. The fact that the rockshelter did not contain any cultural materials apart from skeletal remains (that themselves were related to the 'dwarfs') appears to confirm SK's explanation for the lack of engagement, indeed the complete avoidance, with the rockshelter. The role and reputation of the site's 'dwarfs' as violent beings influenced people's perception of the place.

The Auwim community's use of the specific term, 'dwarfs' (duof or masalai), is likely a Tok Pisin term referring to 'bush spirits', a common term across many parts of PNG that refers to different forms of spiritual entities inhabiting the landscape (see Edwards and Sullivan 2008: 17 for Auwim ancestral spirit and other masalai spirit names). For example, among the Lelet of New Ireland, the 'bush spirits', or lagas, are 'derivations of a basic anthropomorphic body, varying in appearance, size, and their effects on humans' [START_REF] Eves | The failure of therapy: belief, embodiment, and the limits of Pentecostal healing in Papua New Guinea[END_REF](Eves : 9, 1998: 155-157, 160-163): 155-157, 160-163). Some forms of lagas include one that has 'wings and can fly, while others are terrestrial beings, including one with tail and one which is a dwarf' (Eves 2020: 9). Eves notes that lagas are 'powerful beings' and that they have been described as 'cannibals, sorcerers, and tricksters renowned and reviled for their attacks upon humans. These fears are still prevalent, particularly for those who venture into the forest' (Eves 1998: 169).

Thus, the feelings and emotions generated by the Auwim community about Apuranga before the team arrived at Auwim can be embedded in a shared understanding of the violent actions of the 'dwarfs' and the potential for death. This notion of fear associated with place speaks to a growing literature in anthropological and archaeological studies that seek to explore and understand how and why people respond the way they do to encounters with objects, images and places. Over the last two decades, the notions of emotion and affect have been used to add another layer to the study of human behaviour in the past and present. For example, Seigworth and Gregg (2010: 2, original emphasis) note that affect is, 'in many ways synonymous with force or forces of encounter', while Stewart and Lewis (2015: 239) suggest that emotion can be 'a lens for approaching social worlds and lived experiences as ongoing processes, highlighting partiality, flux, and continency'. Stewart's book, Ordinary affects, also show how encounters, experiences and knowledge can 'provoke attention to the forces that come into view as habit or shock, resonance or impact ' (2007: 1). In doing so, this highlights that 'something' has, or is, occurring that can impact on people's behaviour. In a rock art context, recent research (e.g. Brady and Bradley 2016) has explored this theme by examining responses of senior Aboriginal men concerning a well-known and feared rock art site in northern Australia's Gulf of Carpentaria region in the early 1980s. In this instance, the encounter with paintings created by a sorcerer designed to ensorcell and kill victims was the mechanism used to elicit fear. This fear continues to linger into the present day by those who had family members killed by sorcery paintings, and their responses to the site continue to reveal fear, especially for younger generations who may inadvertently visit the site without knowing about its power. In the case of Apuranga, it is the story of the violent 'dwarfs' that can be conceptualised as the 'trigger' for fear among the Auwim, as well as the skeletal remains that act as a tangible reminder of what the 'dwarfs' are capable of doing, that is, killing villagers who go hunting and gathering.

What is intriguing here is that the narrative reveals how an ancestral spirit magician was summoned to assist the Auwim to deal with the 'dwarfs' and the role of memory. While the ancestral spirit magician was able to kill the dwarfs, thus making Apuranga suitable again for visitation, the legacy of the story and the violent actions of the 'dwarfs' clearly remained in the memory of the Auwim until only before the research team's visit, likely contributing to its continuing abandonment/avoidance. Instead, the timing of Auwim re-engagement with the site -coincident with archaeologists interested in rock art -suggests that the presence of researchers may have played some role in this process. Indeed, the testimony of Auwim community members that the stencils were created only after the research team arrived and stated their interests in learning about rock art and other aspects of Auwim cultural history did a transformation of the site occur. Key to this transformation was the inscription of the site with personal markers -hands, feet, everyday objects etc. -as a way of demonstrating the establishment of a new relationship with Apuranga.

This reappraisal of the site's history and the performance of inscribing it with Auwim symbolic markers could, on the one hand, be interpreted as a community's response to the curiosity of the researchers. However, we conceptualise this event as something more complex and embedded in a network of relationships linking the past (violent 'dwarfs' terrorising the Auwim, an ancestral magician killing the 'dwarfs'), present (arrival of archaeologists interested in rock art, prompting a reappraisal of Auwim relationships to a once-feared site) and future (visiting or using the site in the future). What is interesting to consider here is the role of archaeologists in this network. While archaeologists are typically interested in the past and notions of objectivity in their research, their presence and actions can have implications for people's contemporary engagements with places, objects and images. The implications of 'researcher presence' are overlooked in archaeological practice analyses and typically require a reflexive gaze to appreciate their role in people's engagements with their pasts in the present (e.g. Brady 2020). For example, in Torres Strait (north-eastern Queensland) in 2001 and 2002, Ian McNiven, Bruno David and LMB observed rock art being created by Torres Strait Islanders during an archaeological research project on the sacred islet of Pulu. Over two years, the Goemulgal created a total of 37 motifs using locally available red ochre -the first documented occurrence in over 100 years -while participating in an excavation program [START_REF] Mcniven | Pulu culture site mapping project (Torres Strait)[END_REF]; see also [START_REF] Brady | Painting patterns: Torres Strait region rock-art[END_REF][START_REF] Brady | Rock-art from the Mabuyag Islands, Zenadh Kes (Torres Strait)[END_REF][START_REF] Mcniven | The great kod of Pulu: mutual historical emergence of ceremonial sites and social groups in Torres Strait, northeast Australia[END_REF]). The archaeologists did not ask for the motifs to be created, but rather Goemulgal undertook the rock art creation process likely as a performative act in front of archaeologists as a way of reaffirming their powerful relationship to the islet and their cultural practices. What is critical here is that archaeologists can 1) be implicated or embedded in the contemporary process of making rock art; and 2) become integrated into the Auwim's sphere of relationships that shape their engagement with their landscape, memory and cultural practices (see also [START_REF] Taçon | The last rock painters of Kakadu[END_REF] for an example from Kakadu National Park, Northern Territory, Australia).

The production of new motifs at Apuranga is also significant in that they can be conceptualised as active agents used to mediate social relationships. In his work on art and agency, [START_REF] Gell | The technology of enchantment and the enchantment of technology[END_REF][START_REF] Gell | Art and agency: an anthropological theory[END_REF] implored researchers to re-consider art objects beyond their aesthetic values and instead seek to understand how the images or objects exerted their own agency, that is, what can/could they do? He noted that '[t]he idea of agency is a culturally prescribed framework for thinking about causation' (Gell 1998: 16), thus suggesting that interrogating the agency of art objects and images should be carried out according to their social and cultural contexts. Using an example involving the highly decorated Trobriand Islander canoe prows used in the highly competitive kula exchange network, he proposed that they were used to perform 'psychological warfare' on exchange partners, forcing them to give up their most valuable possessions. In the Apuranga context, the new motifs are used to signal changing social relationships: a new relationship based on place-marking to what was a once feared place and that has now been integrated into the Auwim social and cultural landscape, and secondly, a relationship with researchers who are interested in learning more about the nature of Auwim graphic systems and relationships to place.

Conclusion

Our case study involving members of the Auwim community creating rock art stencils at a once feared site has demonstrated that people's contemporary relationships to rock art and place are highly complex. The presence of an archaeological team with interests in rock art has shown that researchers can be embedded in people's cultural traditions and practices, and embedded in their network of relationships involving oral traditions, place-making strategies, and (overcoming) fear. It was this network that resulted in the rock art production of Apuranga. Approaching Apuranga's rock art through the lens of agency, affect and emotion has also been useful in understanding how meaning can be made not only of the motifs themselves but also of the places (e.g. rockshelters) where they are found. The fact that new rock art was created in 2018 is an important and unique case study for PNG and highlights the potential for ethnography to contribute to understanding the nature of rock art in contemporary settings.

Figure 3 .

 3 (a) Trekking to Kundumbue rock art site. (b) An example of a cliff rockshelter at Pundimbung site in the Upper Karawari-Arafundi region, East Sepik, Papua New Guinea in 2018 (Photos: William Pleiber, Papuan Past Project).

Figure 4 .

 4 Examples of different stencil types at Apuranga site in 2018. Left down (a, c and e) before enhancement: a hand/palm, a thumb and unknown leaf stencils, respectively, with the appearance of being recently made. Right down (b, d and f) after picture enhancement using DStretch (yre, crgb, and yre colour filters, respectively) shows no older art (original photos: William Pleiber, Papuan Past Project).

Figure 5 .

 5 Examples of different stencil types at Apuranga site in 2018. Left down

Figure 6 .

 6 View from Apuranga rock art site in 2018 (photo: William Pleiber, Papuan Past Project).

Figure 7 .

 7 Apuranga rock art site in 2018 (photo: William Pleiber, Papuan Past Project).

Figure 9 .

 9 (a) Community leader and co-author, Sebastien Katuk, at another rockshelter in 2018. (b) Research team interviewing a local clan member at Apuranga rock art site (photos: William Pleiber, Papuan Past Project).

Figure 1 .

 1 Figure 1. Map showing the case study area location, Auwim, East Sepik, Papua New Guinea, including other sites mentioned in the text (produced by Andrea Jalandoni; base map by ESRI National Geographic).

Figure 2 .

 2 Figure 2. Auwim village in 2018 (photo: William Pleiber, Papuan Past Project).

Figure 3 .

 3 Figure 3. (a) Trekking to Kundumbue rock art site. (b) An example of a cliff rockshelter at Pundimbung site in the Upper Karawari-Arafundi region, East Sepik, Papua New Guinea in 2018 (Photos: William Pleiber, Papuan Past Project).

Figure 4 .Figure 5 .

 45 Figure 4. Examples of different stencil types at Apuranga site in 2018. Left down (a, c and e) before enhancement: a hand/palm, a thumb and unknown leaf stencils, respectively, with the appearance of being recently made. Right down (b, d and f) after picture enhancement using DStretch (yre, crgb, and yre colour filters, respectively) shows no older art (original

Figure 6 .

 6 Figure 6. View from Apuranga rock art site in 2018 (photo: William Pleiber, Papuan Past Project).

Figure 7 .

 7 Figure 7. Apuranga rock art site in 2018 (photo: William Pleiber, Papuan Past Project).

Figure 8 .

 8 Figure 8. Classification of rock art motifs at Apuranga (following Brady 2005, 2010).

Figure 9 .

 9 Figure 9. (a) Community leader and co-author, Sebastien Katuk, at another rockshelter in 2018. (b) Research team interviewing a local clan member at Apuranga rock art site (photos: William Pleiber, Papuan Past Project).

Table 1 .

 1 List

	Name	Recorder(s)
	Pukan	Gorecki and Jones (1987)
		Tsang (2018)
	Yembinambasekim	Gorecki and Jones (1987)
	Pundimbung (Bundingbum)	Gorecki and Jones (1987)
		Edwards and Sullivan (2008)
		Tsang (2018)
	Kundumbue (Kundumbu)	Edwards and Sullivan (2008)
		Tsang (2018)
	Akuansam (Aekinyam)	Edwards and Sullivan (2008)
		Tsang (2018)
	Apuranga	Tsang (2018)
	Potentially in Auwim Territory
	Takinyaekanga	Edwards and Sullivan (2008)
	Nombokopi	Edwards and Sullivan (2008)
	Kansa	Edwards and Sullivan (2008)
	Imango	Edwards and Sullivan (2008)
	Kantin	Edwards and Sullivan (2008)

of rock art sites recorded in Auwim territory; those potentially in Auwim traditional territory have yet to be verified but are likely to be Auwim, given Sullivan's research base at Auwim village.

A detailed analysis of the site's rock art will be reported as part of Tsang's PhD thesis.

Acknowledgments

We especially thank the Auwim community for their support, hospitality and generosity during our visit between May to June of 2018. Funding for this fieldwork was supported by National Geographic Society Grant (HJ-156R-17 to F-X. R.) for the project 'Prehistory of the Karawari region in East Sepik, Papua New Guinea' (2018). We also thank various funders of the broader project, the French National Research Agency, the French Ministry for Europe, and Foreign Affairs (France), the French Embassy in Papua New Guinea, and University of Papua New Guinea. Thanks are extended to the Papua New Guinea National Research Institute and Papua New Guinea National Museum and Art Gallery for their partnership support. We also thank Professor Hubert Forestier, Professor Joakim Goldhahn, Dr Sébastien Plutniak, William Pleiber and Jason Kariwiga for guidance and motivational discussions. Dr Sally K. May and Emily Miller (Griffith University) are thanked for providing useful comments on drafts of the paper. Andrea Jalandoni is thanked for producing Figure 1. LMB's position is funded through an Australian Research Council Future Fellow grant (FT180100038). PSCT's position is funded by an Australian Research Council Laureate Fellowship (FL160100123). Lastly, we are most grateful to the two anonymous RAR reviewers who took the time to critically read and


Fillipe Luiz
email: fillipelrc@gmail.com

Rosa Do Carmo

Rodrigo Dias
email: rodrigodoc2@gmail.com

Oliveira Carvalho

Emiliano Sara Heloisa Da Silva

Rosa Oliveira

Denise Carmona
email: deniseccm@gmail.com

Ana Maria Caetano Faria
email: anacaetanofaria@gmail.com

Houem Rabah
email: houyemrabah1990@gmail.com

Barbara Fernandes Cordeiro

Emiliano Rosa Oliveira
email: emiliano.roliv@gmail.com

Luisa Lemos
email: luisalemossantos@gmail.com

Denise Carmona Cara

Gilles Garric
email: gilles.garric@inra.fr

Marielle Harel-Oger
email: marielle.harel-oger@inra.fr

Yves Le Loir
email: yves.le-loir@inra.fr

Vasco Azevedo

Guillaume Bouguen
email: guillaume.bouguen@chu-rennes.fr

Benoît Foligné
email: benoit.foligne@univ-lille.fr

Gwénaël Jan
email: gwenael.jan@inrae.fr

Assembling immunomodulatory strains of Propionibacterium freudenreichii, Lactobacillus delbrueckii and Streptococcus thermophilus to produce an anti-inflammatory Emmental cheese

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

Introduction and Aims. Inflammatory Bowel Diseases (IBD), including Ulcerative Colitis (UC), coincide with alterations in the gut microbiota. Consumption of immunomodulatory strains of probiotic bacteria may induce or prolong remission in UC patients. Fermented foods, including cheeses, constitute major vectors for bacteria consumption. New evidences revealed antiinflammatory effects of selected strains within the species P.freudenreichii, S.thermophilus and L.delbrueckii. We thus hypothesized that consumption of a functional cheese, fermented by selected strains of these three species, may exert a positive effect on IBD.

Methods. Strains of each bacterial species were screened based on the ability to induce regulatory IL-10 in human immune PBMC cells, or to downregulate nuclear factor kappa B (NF-κB) activation in a cultured HT-29 human intestinal epithelial cell line. We then investigated the effect of monostrain experimental cheese. We further investigated the impact two-strains experimental cheese. Finally, we produced in industrial conditions an Emmental cheese using one selected strain of each of the three species, i.e. P. freudenreichii CIRM-BIA 129 in combination with Lactobacillus delbrueckii CNRZ327 and Streptococcus thermophilus LMD-9. Consumption of all cheeses was investigated with respect to prevention of chemically induced colitis in mice.

Results. Consumption of the experimental cheeses, or of the industrial Emmental, reduced the severity of subsequent chemically induced colitis, weight loss, disease activity index and histological score, in mice. Furtherrmore, consumption of the Emmental cheese, in a preventive way, reduced small bowel Immunoglobulin A (IgA) secretion, restored occludin gene expression and prevented induction of Tumor Necrosis Factor α (TNFα), Interferon γ (IFNγ) and .

Conclusion.

Assembling immunomodulatory strains of both lactic acid and propionic acid starter bacteria leads to an anti-inflammatory Emmental cheese, as revealed in vivo. This opens new perspectives for the development of functional fermented food products for personalised nutrition in the context of IBD. Keywords: probiotic; colitis; cheese; inflammation; Propionibacteria; Emmental; intestine; Inflammatory Bowel Disease


Christian Adam

Marion Pupier

Jean-Marc Nuzillard

Julien Wist

Nils E Schlörer

Mate Erdelyi Stefan Kuhn

Mate Erdelyi e Christoph Steinbeck

Antony J Williams

Craig Butts

Tim D W Claridge

Bozhana Mikhova

Wolfgang Robien

Hesam Dashti

Hamid R Eghbalnia

Christophe Farès

Pavel Kessler

Fabrice Moriaud

Mikhail Elyashberg

Dimitris Argyropoulos

Manuel Pérez

Patrick Giraudeau

Roberto R Gil

Paul Trevorrow

Damien Jeannerat
email: damien.jeannerat@unige.ch

NMReDATA, a standard to report the NMR assignment and parameters of organic compounds

Keywords:

come

Introduction

Exploiting the NMR spectra of compounds consists of extracting the NMR parameters, which we call NMReDATA (for "NMR extracted data"), including chemical shift values, scalar coupling constants, 2D correlations, etc. and assigning them to a chemical structure. The reliability of the structure determination depends heavily on the accuracy and extent of the NMReDATA, which needs to be reported in a format compatible with a maximum number of software packages. Herein, we introduce a file format to effectively associate these NMReDATA with the assigned structure. [1] These electronic reports will be generated by software assisting chemists in the interpretation of spectra, or by using tools to create them in the case where the spectra were interpreted using "paper and pencil". The commercial software providers Bruker, Mestrelab Research, Advanced Chemistry Development (ACD/Labs), and the non-commercial software platform Nmrshiftdb2 [2] and C6H6.org [3] , have all committed to use the format in future releases of their products. These formatted NMReDATA will facilitate the accessibility and exchange of the partial or full structure assignment within the chemistry community. More importantly, it will constitute an easier way for the inspection and verification by reviewers because the data will be suitable for submission to scientific journals. Simply opening the NMReDATA file will permit a user to interrogate and confirm the assignments associated with the signals in the spectra. This contrasts with the current unsatisfactory situation where NMR parameters are dispersed in peak lists, tables of correlations and low-quality image-based spectra typically located in supplementary material, commonly in PDF format only and thereby making it difficult for both humans and computers to access and assess the data. [4] Because of the need to keep both the NMReDATA and the associated spectra together to allow for verification of their consistency, we have also introduced the concept of "NMR record". An NMR Record is a compressed folder including the NMReDATA file and all related 1D and 2D spectra (see Figure 1) including the raw data (i.e. the FIDs and all the acquisition and processing parameters). Such NMR records will also be optionally exported and imported by NMR software packages such as CASE (Computer-Assisted Structure Elucidation) software [START_REF] Elyashberg | Contemporary Computer-Assisted Approaches to Molecular Structure Elucidation[END_REF] and could be submitted with manuscripts for publication. For Magnetic Resonance in Chemistry, the requirement that all "spectral assignment" manuscripts submissions be accompanied by full NMR records was announced recently and will be gradually enforced during 2018. [START_REF] Gil | [END_REF] Other journals have demonstrated interest in this initiative and may follow suit. The intention of the NMReDATA initiative is the following: When journal articles are accepted for publication, the associated NMR records are deposited with keywords and metadata about the publication in open databases, thereby making them permanently available to the community. The database should provide a DOI (Digital Object Identifier) to ensure stability of the data. Making spectral data available should also satisfy the "Open Data" requirements of a growing number of funding bodies. Note that related efforts, e.g. NMR-STAR [7][8][9][10] and nmrML [11] intend to cover the maximum number of data types and focus on the homogenization of the vendor-specific parameters. In contrast, the NMReDATA initiative can be seen as intends to restrict to a core set of parameters relevant to support structure determination. It structures data on two layers: the NMR parameters associated to individual spectra, and the ones used for the assignment. This should facilitate the interoperability of the experimental spectra and their associated meta-data and facilitate the validation of the data.

Structure Data Format (SDF)

The NMReDATA are associated with a chemical structure using the Structure Data Format (SDF) file. This file format was introduced by Molecular Design Limited (MDL) to associate one or more chemical structures with diverse types of data. [12] The structures are encoded in the commonly used MOL (.mol) format, also introduced by MDL, dealing with 2D and 3D structures with and without implicit hydrogen atoms. The additional data are included in the file in the form of property value pairs called "tags" (see Figure 2). SDF files can be considered as MOL files with additional metadata. This file format is the primary import and export format for chemical structure drawing software packages. It is also used by the vast majority of publicly available chemistry databases (e.g. PubChem, [13] ChemSpider, [14] ChEBI [15] ) and across the field of cheminformatics to associate chemical structures with properties, e.g. solubility, affinity to a drug target, or more trivial information such as storage locations. Thus, the nmredata.sdf files will include the assigned chemical structure (black in Figure 2), the NMR data (and possibly some non-NMR data), in a compact and convenient manner (see tags in Figure 2). Structure visualization software suites (such as ChemDraw, [16] Jmol, [17] etc.) will open the SDF files and only display the chemical structure encoded in MOL file format, while NMR software packages will be able to access the NMReDATA tags and allow for their visualization, manipulation, validation, etc.

Chemical structure

A key requirement of an NMR assignment is to report the structure of the compound appropriately. The soundness of a molecular structure can be judged, if not proven, by the quality of the pairing of its structural features with its extracted NMR parameters. Indeed, depending on the data quality and requirements, an NMR characterization may be reported with different levels of structural precision. In the simplest case, one may only be able (or wish) to determine the connectivity of atoms (sometimes called "flat structure") with no additional information about the three-dimensional structure (see Figure 3A). In some cases, the exploitation of specific NMR parameters (e.g. a scalar coupling) may provide a local structural feature (e.g. the relative configurations of a pair of carbons as shown in Figure 3B). Finally, in the most exhaustive cases, the full analysis of the coupling constants, NOE data, anisotropic parameters or the knowledge of the absolute configuration obtained by non-NMR means, allows the unambiguous configuration of all chirality elements of the molecule to be specified as in Figure 3C. In all cases, it is important to use a representation of the structure reflecting the available knowledge in order to avoid under-or, more problematically, overinterpretation. Note that given the inability of NMR to determine absolute configuration with classical methods, one should always consider the absolute configuration of the reported structures as not being ascertained.

The choice of which degree of structural certainty to include in an NMReDATA file also depends on the completeness of the assignment. When the protons of the methylene groups of menthol are only assigned to their directly attached carbons, a structure with implicit hydrogen atoms is appropriate (Figure 3C). But when axial and/or equatorial protons are discriminated (typically through the observation of a large trans-diaxial coupling constant), a structure with explicit protons is necessary to unambiguously assign the two hydrogen atoms (see Figure 3D).

In general, chemical structures can be expressed with InChI strings. [18] But replacing the MOL structure with the InChI string, can only be done if the numbering of the atom is unique and unambiguous. This can be done using the ALATIS code [19] (where ALATIS stands for Atom Label Assignment Tool using InChI String). In the context of NMReDATA, we therefore recommend the structure part of NMReDATA to use the ordering of the atoms of ALATIS-generated structures. This allows one to safely replace the structure with an ALATIS code, making it possible to generate puretext assignment reports where the assignment is performed using atom indices (see section 7). 9)11/h7-11H,4-6H2,1-3H3/t8-,9+,10-/m1/s1 as reported by ALATIS. Note that even if the chirality of menthol is fully determined, the assignments of carbon 1 and 2 are usually not unambiguously assigned because it has no consequence on the determination of the structure.

NMReDATA tags in SDF files

NMReDATA are encoded using a set of tags (see Figure 2 and Table 1). The tag names start with the prefix "NMREDATA_" in order to avoid confusion in those cases where the SDF files also include property types other than the NMR related ones. The NMReDATA Initiative [1] defined, for its version 1, the set of "tags" listed in Table 1. It is recommended to follow the order of Table 1. List the peaks extracted from 1D spectra (see Table 4)

NMREDATA_2D_ Isotope (F1)_Code of the mixing_ Isotope (F2)

List peaks extracted from 2D spectra (see Table 5)

1 Refer to the website of the Initiative for more details.

[1]

2 A non-zero value indicates the presence of ambiguous assignment (see section "Ambiguities").

General information about the sample and the NMR experiment

A minimal set of information about the sample and the performed NMR experiments is part of the NMReDATA format. It includes the solvent composition, the temperature and, when known, the concentration of the compound. The spectrometer magnetic field is not listed here, but can be inferred from the Larmor frequency of the detected nuclei for each NMR spectrum (see below).

Other data, such as the equipment used, pulse sequences, pulse durations, referencing, etc. are not part of the format, but can be searched in the acquisition and processing parameters that are present in the associated NMR record.

We strongly recommend to include the chemical formula, the SMILES and InChI code, but only if they truly reflect the associated chemical structure. These can facilitate searches in online databases. If they are not present in NMReDATA generated by the NMR software, they should be added before they are made available on databases.

The Assignment Tag

The assignment tag contains, for each atom label used in the assignment of the spectra, the chemical shift (with adequate number of decimal places [20] ) and the list of atom indices they refer to (see Figure 2). Symmetry properties, such as the degeneracy resulting from the fast rotation of methyl groups, can be expressed by associating to a label, the list of indices of the atoms it refers to (i.e. the ones of the three hydrogen atoms). Similarly, the non-equivalent protons of a CH2 will be usually designated with a single label. If necessary, for example in cases of magnetic non-equivalence (see Figure 4) and when different coupling constants need to be reported, the two hydrogen atoms should have different labels allowing the coupling constants to be assigned to a given coupling partner. In this case, the identical chemical shift will indicate the chemical equivalence. In general, the list includes reference to carbon, fluorine, phosphorus, etc. atoms when their spectra are part of the NMR record. (B) When ignoring the complex structures of the AA'BB' system, the protons can be described using a single label ("a" and "b"). (C) When the coupling constants were extracted using optimal fitting with spectral simulations, distinct labels for the equivalent protons (a, a', b, b') are necessary to report all coupling constants using a NMREDATA_J tag (see next paragraph). Note that because hydrogen atoms were implicit in structure (A), "H" was added and the indices of the atoms are the ones of the directly attached heavy atoms.

The redundancy of the reporting of the chemical shifts and coupling constants with respect to the description of the 1D spectra (see below) is deliberate. The compilation of the data found in a set of spectra facilitates access to these essential NMR parameters, avoiding the need to search and analyze the values found in the individual 1D and 2D spectra. Another reason is that in some spectra, the chemical shifts may be reported in an ambiguous manner reflecting the limits of the specific experiment. For example, a set of protons may overlap in a 1D 1 H spectrum and the chemical shift reported as a broad chemical shift range, while an HSQC or a J-resolved spectrum may provide clearcut values for each individual chemical shift. The chemical shifts in the assignment tag can be seen as the aggregation of the chemical shift measured through the set of NMR spectra of the record.

The J-coupling tag

In some situations, the analysis of the scalar coupling constants is essential for the determination of chemical structures. By analogy to the compilation of the chemical shift, the NMReDATA format defines a tag to list all of the assigned coupling constants. Typically, the JHH and JCH are used to determine the 3D structure of natural and synthetic products (see the example of menthol in Fig. 5). In other cases, such as when measuring long-range JCH constants or when reporting 1 JCH including residual-dipolar coupling, the list will contain only (or mostly) 2,3 JCH or 1 DCH respectively. Obviously, other couplings such as JCF, JHP, etc. can also be included. 3 J and 4 J respectively originating from the spectral tag (see following sections). When known, the signs of the coupling constants should be specified, otherwise the absolute values are listed. Optionally, the number of bonds between the pair of spins can be specified after "nb=". (eg. "Me3, H8aq, 6.58, nb=3").

Tags describing spectra

For each spectrum included in NMR records, a spectral tag will contain the extracted information. The name of the tag (see Table 2) encodes the type of spectrum (1D v/s 2D), and the detected isotope. For 2D correlation spectra, the isotope evolving during t1 and the type of mixing is specified before the detected isotope. NMREDATA_2D_13C_1J_1H 2D spectrum with 13 C evolution during t1, 1 H evolution during detection and 1 J mixing (HSQC, or HMQC experiments) NMREDATA_2D_1H_NJ_1H 2D COSY spectrum 1 More details can be found on the website of the NMReDATA initiative.

[1]

Before listing the peaks extracted from the spectra, a header provides important characteristics of the spectrum using the keywords (see Table 3). The Larmor frequency of the detected isotope follows "Larmor=". Decoupling or absence of decoupling (when it is assumed by default -as for HSQC, HMBC spectra) is specified using "Decoupled=isotope" and "NonDecoupled=isotope". Specifying the type of experiment ("CorType=", COSY, HSQC, etc.) is particularly important to allow the verification of the compatibility of the reported NMR parameters with the chemical structure (see Validation of NMReDATA). The format of the peak list differs for 1D and 2D spectra, and is discussed in the next two sections.

A pointer to the original spectrum (with FID, acquisition and processing parameters in the crude original format of the manufacturer) is mandatory to permit verification (or refinement, correction, etc.) of the NMReDATA. The "Spectrum_Location=" is a directory path, relative to the root of the zip file, pointing to the spectrum. When the NMR record is available in a web-accessible database, the HTML link having as prefix a DOI (to insure reliability of data access) and pointing directly to the readily downloadable zip file of the record is also specified.

Spectrum_Location = Path to the spectrum relative to the root of the NMR record

Pulseprogram = Name of the pulse program

1 For HSQC and HMQC experiments proton and carbon decoupling is implicit in F1 and F2 respectively. For HMBC experiments proton decoupling is implicit in F1.

Peak list of 1D spectra

For each signal extracted from 1D spectra, one line lists its parameters. The first field is the chemical shift or chemical shift range. The others, called "attributes", provide additional information such as multiplicity, integral, assignment, etc. (See the complete list in Table 4). An example of a multiplet described using various level of details is given in Figure 6.

Note that not all NMR parameters will be reported depending on the ambition of the user, the quality of the spectra and the capabilities of the software package used to analyze the spectra. The type and the number of peak attributes reported in the NMReDATA will therefore reflect the level of detail of the analysis and may be quite sparse. Note that if the software generating the NMReDATA does not allow for the assignment of the coupling partners (Figure 6H), a program identifying that couplings with (nearly) identical values are found for protons that are known to be two or three bonds away could be used to assign coupling constants (Figure 6I) and construct the coupling network (Figure 5). As mentioned earlier, more sophisticated tools using spectral simulations [21][22][23][24] could further increase the reliability of the assignment and the precision of the coupling constants, and also provide reliable spectral parameters (chemical shifts and scalar coupling constants) in strongly coupled systems.

Peak list of 2D spectra

For each 2D spectrum, the pairs of correlated signals are listed on separate lines. Other signal properties such as the intensity (either at the exact coordinates of the chemical shifts of signals or slightly off to avoid minimal values in the middle of doublet, or antiphase patterns) are optional (see Table 5). Even if it is still uncommon to measure coupling constants in the multiplet structure of highresolution 2D COSY spectra, [25] NMReDATA has the capability of incorporating the results of such an analysis (see Figure 7B for an example).

Note that even if this is normally not used, the NMReDATA format allows the inclusion of unassigned cross peaks; in these cases, to define a signal, one can use the corresponding chemical shift values of the signals in place of the atom labels. This allows simple peak-picking software to generate NMReDATA files, which can be updated by a subsequent assignment process. Note as well that when the NMReDATA files are used to report assigned data, unassigned signals may be ignored.

Validation of NMReDATA

By providing electronically readable NMR spectral parameter sets, NMReDATA files allows the manual or automatic verifications of the reported data [26][START_REF] Robien | Progress in the Chemistry of Organic Natural Products[END_REF][START_REF] Nicolaou | [END_REF] and the evaluation of the soundness of the determined structure. In the following paragraph, we shall only present a broad overview of how this is in principle possible, without discussing the known difficulties associated with automated analysis. We will consider a typical set of spectra used for a structural analysis of an organic compound (often called "full analysis") that is usually 1D 1 H and 13 C/DEPT-135 and 2D COSY, HSQC, and HMBC spectra. Note that some of the possibilities listed below are already being introduced on commercial software like ACD/Spectrus, [29] CMC-se, [30] Mnova [31] and other non-commercial platforms such as C6H6. [3] Having the associated chemical structure and the description of 1D 1 H and 13 C spectra at hand allows for the determination of whether all protons and carbons have been documented. One of the difficulties in this process is the possibility of degenerate signals resulting from symmetry, which can be overcome by the assignment of a tag listing the equivalent atoms or the presence of multiple signals with the exact same chemical shifts. In such a way, a program could take into account the nature of the solvent to consider whether the proton from OH or NH are expected to exchange with the ones of the solvent. We encourage that exchanging protons be named "Ex". Note that in the case of menthol, the hydroxyl proton is not exchanging (as demonstrates the coupling with H10ax) otherwise it would have been called "Ex". This name will indicate to an automatic verification program that a group of protons assigned to a single signal is not due to symmetry, a property which can be assessed using cheminformatic tools such as CDK. [32] A verification of the reported multiplicity of signals can be performed regarding the spectrum and the chemical structure. Simply considering that multiplicity should include one "d" for each spin 1/2 located 1 -3 bonds from the reference nucleus and keeping in mind that "t" counts for two couplings, "q" counts for three, etc. should be enough in most cases. More sophisticated methods could take into account nearby spins >1/2 (such as 2 D, 11 B, 17 O) or elements with multiple isotopes (resulting to the small doublet due to the minor 29 Si isotope or the two doublets due to the 117 Sn and 119 Sn isotopes). The values of the coupling constants could also be taken into account. A simulation of multiplets could be compared to the experimental spectrum using the reported values of the couplings and optionally using predicted values of the coupling constants. [33] Note that second-order effects could be anticipated by observing, from the NMReDATA, that coupling partners present a small difference in chemical shifts. Determining the coupling constants, even in the case of strong coupling and magnetic equivalence, should be possible by spectral simulation and fitting procedures found in SPINACH [21,22] (all kinds of spectra), ANATOLIA [23] (currently only 1D 1 H spectra) or GISSMO. [24] The 2D correlations reported in NMReDATA can also be verified by checking the presence of signals at the coordinates of the chemical shifts of the correlated spins. The consistency of the reported data with the structure can also be tested by simply verifying that the number of bonds between the correlated spins is compatible with experiments based on scalar coupling (1 HSQC, 2, 3, (4) for COSY and HMBC data). More sophisticated tools such as Logic for Structure Determination (LSD) [34] can confirm that the structure is compatible with the NMReDATA, and when the structure is not uniquely determined, LSD provides the user with the list of the alternative structures fully compatible with the spectral data.

Quality factors based on the comparison of the experimental chemical shifts and coupling constants with predicted ones [2,33,35,36] could be easily calculated from the NMReDATA.

Ambiguities

Ambiguities are commonplace in NMR assignment. In some cases, ambiguous assignment has no consequence on the determined structure. For example, the inability to assign two methoxy groups does not mean that the structure does not have two OMe, but only that their assignments could not be determined. At a different level of the assignment, the lack of resolution of an HSQC spectrum may not allow unambiguous assignment of a pair of carbons (resulting to the quite common "these carbons are interchangeable") but still permit the determination of a structure. These two types of ambiguities were introduced into the NMReDATA format. Because dealing with ambiguities complicates the visualization of the data, we introduced a tag called "NMREDATA_LEVEL" to indicate when ambiguities are reported in the NMReDATA. This allows software tools that are not able to deal with ambiguities to reject such data and facilitate the quick development of programs dealing with the most common non-problematic cases.

Ambiguities in the assignment of spin

The first type of ambiguity occurs at the level of the assignment when a single chemical shift is associated with a list of atoms in the structure. It consists of listing a set of signals/labels for which a set of different assignments is possible (see Table 6). Another assignment ambiguity case occurs, for example when a methoxy group (with 1 H and 13 C labeled "CH3a" and "Ca", respectively) is not distinguished from a second methoxy group because of a lack of signal in the HMBC spectrum. One way to deal with NMReDATA with this type of ambiguities consists of duplicating (or multiplicating when ambiguities include more than two possibilities) the table of references to the atom indices. These types of ambiguities can be dealt with by considering a set of possible atom numbering tables (instead of a unique one). 6.2 Ambiguities in the assignment of a peak Ambiguities can also be specified at the level of the assignment of a peak to a 1D or 2D spectrum, for example if an HMBC signal is too broad in the indirect dimension to point to only one carbon (see the fourth entry in Table 7). In such a case, possible candidate signals are listed in parentheses. One consequence of the presence of such ambiguities is that the validation tool should use a logical "or" on the list of possible assignments. After a header announcing "NMReDATA" and its version number, the chemical structure is encoded using the ALATIS format. This ensures that all information about the structure is retained and that the sequence of atoms is unambiguous. This allows the replacement of assignment tag labels with indices of the atom in the ALATIS format within double quotes. Then follows the compilation of chemical shifts and (when present) the assignment of the couplings. Afterwards, for each 1D spectrum, the chemical shifts are listed with the most relevant attributes in parentheses and the DOI and path pointing to the specific spectrum within the record. Finally, for each 2D spectrum, the list of correlated signals is given by direct reference to the atoms indices.

Note the absence of italics, Greek letters, or sub-or superscripts, facilitating the extraction of the text and making it possible to compress the text as QR codes for example.

Analysis of mixtures

Because the NMR record includes the spectra of a given sample it may, by nature, contain multiple components (mixtures, slowly exchanging isomers, etc.). In cases where more than one compound is associated with an NMR record, one should simply generate one NMReDATA file per assigned compound (see Figure 8).

Conclusion

Despite the wide application of NMR for the study of small molecules, there is no standardized procedure for the exchange of structure related NMR parameters between software suites. As a consequence, retrieving different types of experimental information from reports and publications has been a challenge in the NMR community. Herein, we addressed this challenge by developing a data structure for NMReDATA records (Version 1.0) in a concise human-and machine-readable format. It results from the collective work by a wide range of stakeholders including, experts in structure elucidation, software developers and journal editors. The format will foster the generation and the exchange of NMR data, and facilitate their validation by chemists, NMR experts, authors and reviewers of publications, and, finally, all users of the published data. The urgent need of an electronic data format in combination with an open-access repository of NMR spectral data is further supported by the large number of wrong structures found in the literature [START_REF] Robien | Progress in the Chemistry of Organic Natural Products[END_REF][START_REF] Nicolaou | [END_REF] and the difficulty in revising them.

After integration of the new format into NMR software, the generation of NMR records including the NMReDATA files will take no additional time. A "save as..." option or a simple copy/paste is all that will be necessary to save or transfer NMR records to dedicated NMR databases such as cheminfo.org. When deposited for review, they will initially be embargoed and only accessible to the reviewers using a coded URL included in the manuscript. When the article is published, the NMR records will become open to the public and relevant records could be merged into databases such as C6H6.org, [3] nmrshiftdb2, [2 , 37] which contents will become part of C6H6.org, BMRB, [10] ChemSpider [14,38] and Metabolights. [39] The NMReDATA initiative collaborates with the Biological Magnetic Resonance Bank [10] to develop interfaces between the NMReDATA and the NMR-STAR [7][8][9][10] data formats. These interfaces are designed to guarantee seamless access to reference metabolites from BMRB in NMReDATA data format, and also to readily deposit published NMReDATA data into BMRB.

Version 1 of the format should be seen as a compromise, which may evolve in order to integrate new features as motivated developers join the initiative. A future release could address the question of the format of the raw spectra, and additional requirements for the Open Data initiative. Currently, NMR records can include any format generated by spectrometer manufacturers -only the NMReDATA per se are standard -but accepting a single standard for the spectra would further simplify the utilization of NMR records.

We believe that in the future, all users of NMR data will have access to software packages allowing them to easily check chemical structures for consistency with all experimental data used for structure verification or elucidation. [START_REF] Elyashberg | Contemporary Computer-Assisted Approaches to Molecular Structure Elucidation[END_REF] This shall significantly reduce the number of wrong structures published in chemical journals.

Figure 1 .

 1 Figure 1. An "NMR record" consists of a compressed folder in .zip format and includes a set of NMR spectra with the time domain FIDs, the acquisition and processing parameters (in green), and the NMReDATA file (.nmredata.sdf file in orange) containing a chemical structure and the extracted NMR data.

Figure 2 .

 2 Figure 2. Pictorial representation of the content of an SDF file included in NMR records. It consists of a structure (in black) and the NMR extracted data (NMReDATA tags). The property value pairs comprise information on the sample (blue tags), compilations of the chemical shift and scalar coupling information (red tags) and descriptions of 1D and 2D spectra (brown tags).

Figure 3 .

 3 Figure 3. Different levels of interpretation of the NMR spectra of menthol. (A) The absolute configuration of the carbons is unknown. (B) The relative configuration of carbons 9 and 10 is defined based on the observation of a characteristic large trans-diaxial coupling (J > 10 Hz). (C) The chirality is fully determined. (D) Structure with explicit hydrogen atoms depicted for unambiguous assignment of the pairs of non-equivalent protons of the methylene groups. (E) Representation and ALATIS numbering of non-equivalent atoms. (F) True 3D model structure with all hydrogen atoms, including equivalent ones, with ALATIS numbering. InChI=1S/C10H20O/c1-7(2)9-5-4-8(3)6-10(9)11/h7-11H,4-6H2,1-3H3/t8-,9+,10-/m1/s1 as reported by ALATIS. Note that even if the chirality of menthol is fully determined, the assignments of carbon 1 and 2 are usually not unambiguously assigned because it has no consequence on the determination of the structure.

Table 1 .

 1 NMReDATA tags names and content (Version 1.0mixture of solvent with their proportions, etc. NMREDATA_ID Doi=... DOI of the NMR record Record=... URL pointing to the directly accessible ziped record Path=... Location of the nmredata.sdf file relative to the root of the NMR record ... Other references can be added by the software packages generating the files and the databases storing them. NMREDATA_TEMPERATURE Temperature of the sample during the NMR acquisition. (in Kelvin) NMREDATA_CONCENTRATION (optional) Concentration in mM NMREDATA_LEVEL Specify the complexity of the content of the NMReDATA files 2 NMREDATA_FORMULA Chemical formula of the compound NMREDATA_INCHI InChI string of the chemical structure NMREDATA_ALATIS Standard InChI string of the chemical structure as generated by ALATIS NMREDATA_ASSIGNMENT Associate the labels used for the assignment to a chemical shift and the atom numbers in the chemical structure NMREDATA_J Compile assigned scalar couplings (only present when couplings were assigned) NMREDATA_1D_Isotope

Figure 4 .

 4 Figure 4. Examples of NMREDATA_ASSIGNMENT tags for the description of the 1 H spectrum of orthodichlorobenzene (A). For simplicity only hydrogen atoms were listed in the figure.In general, the list includes reference to carbon, fluorine, phosphorus, etc. atoms when their spectra are part of the NMR record. (B) When ignoring the complex structures of the AA'BB' system, the protons can be described using a single label ("a" and "b"). (C) When the coupling constants were extracted using optimal fitting with spectral simulations, distinct labels for the equivalent protons (a, a', b, b') are necessary to report all coupling constants using a NMREDATA_J tag (see next paragraph). Note that because hydrogen atoms were implicit in structure (A), "H" was added and the indices of the atoms are the ones of the directly attached heavy atoms.

Figure 5 .

 5 Figure 5. (A) Example of a J-coupling tag. (B) Corresponding 1 H-1 H coupling network. The all-equatorial substitution of the cyclohexane ring of menthol can be deduced from the six characteristically large coupling constants (> 8 Hz) of pairs of axial protons. Thick, normal and dotted lines represent 2 J,3 J and 4 J respectively originating from the spectral tag (see following sections). When known, the signs of the coupling constants should be specified, otherwise the absolute values are listed. Optionally, the number of bonds between the pair of spins can be specified after "nb=". (eg. "Me3, H8aq, 6.58, nb=3").

Figure 6 .

 6 Figure 6. Examples of descriptions of the same 1D 1 H signal. (A) Multiplet of proton H10 of menthol. (B) Tag name and spectral characteristics of the 1D 1 H spectrum. (C) Signal defined as a chemical shift range with the crude integral. (D) Normalization of the integral to one proton. (E) Signal identified with a single chemical shift with an "m" multiplicity. (F) Signal with only its peak intensity, typical for 1D 1 H decoupled 13 C spectra. (G) Signal identified as a "dddd" and assigned to the proton H10ax. (H) The coupling constants measured in the multiplet are listed and assigned in (I).

Figure 7 .

 7 Figure 7. Examples of NMReDATA tag of 2D spectra of menthol. (A) Assignment of region of interest of a 2D HSQC spectrum. (B) Cross peak between the protons H4eq and H6eq of a high-resolution DQF-COSY spectrum illustrating how coupling constants can be included in the NMReDATA without (C) or with assignment (D).

Figure 8 .

 8 Figure 8. Structure of the NMR record of a sample containing the two slowly exchanging isomers of glucose. Two NMReDATA files (compound1.nmredata.sdf and compound2.nmredata.sdf) corresponding to the two anomers of glucose are included in the NMR records.

Table 2 .

 2 Nomenclature of spectral tag names 1

	Tag name	Type of spectrum
	NMREDATA_1D_1H	1D 1 H spectrum
	NMREDATA_1D_13C	1D 13 C spectrum
	NMREDATA_1D_13C#2	Second 1D 13 C spectrum (for example, for DEPT spectrum)

Table 3 .

 3 Spectral properties (1D and 2D spectra)

	Keyword	Spectrum property
	Larmor=value in MHz	Larmor frequency of the detected isotope
	CorType=type	Type (1H, 13C, DEPT135, COSY, HSQC, etc.)
	Decoupled=isotope	List of decoupled isotopes 1
	Nondecoupled=isotope	Denies implicit decoupling 1

Table 4 .

 4 Peak attributes of 1D spectra

	Key letter Peak attributes	examples
	-	Chemical shift	4.1238
	-		4.1312-4.1278
	S=	Multiplicity	s, m, d, t, dd, etc.
	J=	Scalar coupling constants	9.90
			9.90 (H9ax)
	N=	Number of nuclei	1, 2, 3, etc.
	L=	Assignment (label)	H10ax
	E=	Integral (crude)	99.87

Table 5 .

 5 Peak attributes of 2D spectra

	Key letter Peak attributes	examples
	-	Assignment of the peak F1/F2	C10/H10
	E=	Volume (crude)	7.34E6
	I=	Signal intensity (relative)	1.67E5
	W1 =	Width at half height in F1 (Hz)	2.3
	W2=	Width at half height in F2 (Hz)	1.3
	Ja=	Active scalar coupling (Hz)	10.9
	J1 =	Passive scalar coupling in F1 (Hz)	5.60
	J2=	Passive scalar coupling in F2 (Hz)	7.34
			9.90(H9ax)
	T1=	T1 relaxation time (s)	1.54
	T2=	T2 relaxation time (s)	1.24

Table 6 .

 6 Ambiguities in the assignment tag

		Example	Meaning
	1	Interchangeable=Ha, Hb	The spins Ha and Hb may be interchanged
	2	Interchangeable=(CH3a, Ca), (CH3b, Cb)	The spins of CH3a together with Ca,
			may be interchanged with those of the
			(CH3b, Cb)

Table 7 .

 7 Ambiguities in spectral tags

	Example	Meaning
	1 1.2324, L=Ha	Unambiguous assignment of 1D signal
	2 1.2324, L=(Ha|Hb)	The signal is assigned to either Ha or Hb.
	3 Ha/C1	Unambiguous assignment of a 2D signal
	4 Ha/(C1|C2)	The signal is assigned to C1 and/or C2 in the F1 dimension
	5 (Ha|Hb)/(C1|C2)	The signal is assigned to one or more of the
		four possible combinations Ha/C1, Ha/C2, Hb/C1 and Hb/C2

Acknowledgements D.J. and M.P. thank the State of Geneva and the Swiss NSF (grant no. 200021_147069 and 206021_128746) for funding. H.D. and H.R.E are supported by the U.S. National Institutes of Health (NIH) grant P41GM103399 and P41GM111135 (NIGMS). NES gratefully acknowledges funding by the Deutsche Forschungsgemeinschaft (DFG, IDNMR project, Grant SCHL 580/3-1). John Markley is thanked for useful discussions and for comments on the manuscript. Emma Schymanski and Andrew McEachran are acknowledged for their valuable comments in the final stage of review. Disclaimer: The views expressed in this paper are those of the authors and do not necessarily reflect the views or policies of the U.S. Environmental Protection Agency. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

Pure text descriptions

In many cases such as reports, PhD theses, etc. a text document is used to report spectral assignments and including the content of NMReDATA files may not be possible or desirable. We therefore support a textual form of the core information of nmredata.sdf files for cases without ambiguities. It consists in a single line of text composed of the content of the second column of the Table 8. (See the Supplementary material for an example). Larmor frequency 2 , solvent 3 , temperature 4 ):

14 text1/text2 "text1"/"text2" 1 15 Path=path 5

1 A comma followed by a space is added as separator between entries. A period followed by a space is added after the last entry. 2 From the "Larmor=" property of 1D and 2D spectra. 3 From the NMREDATA_SOLVENT tag. 4 From the NMREDATA_TEMPERTURE tag. [START_REF] Elyashberg | Contemporary Computer-Assisted Approaches to Molecular Structure Elucidation[END_REF] From the "Spectrum_Location" properties of 1D and 2D tags. [START_REF] Gil | [END_REF] Either the isotope of the spectrum (1H, 13C) (without superscripts) or the name of the pulse sequence (DEPT135, DEPT90, etc.). 7 In the absence of comma to list multiple atoms, the "<" and ">" delimiters are not mandatory. 8 From the "CorType=" of property of 2D tags.

Graphical abstract

Text of the graphical abstract:

A format for the data extracted from a set of NMR spectra (chemical shifts, coupling constants, 2D correlations, etc.) will make easier to report, compare, verify, validate, share and archive NMR data relevant to structure determination.