Newcomer object ownership negotiations when transitioning from home care to early childhood education and care in Finland

ABSTRACT

For those experiencing them, educational transitions include not only the present time but are embedded within institutions that precede and extend beyond the individuals. This article explores how, as an institutional space, the early childhood education and care (ECEC) setting is (re)produced within young children’s encounters with others during a transition period. Video-recorded observations of three infant-toddlers’ first months of attendance to an ECEC setting were analysed following analytic induction and video interaction analysis. Two examples illustrating object ownership negotiations are discussed. The results show that, in their encounters with others, newcomers actively contributed to (re)producing the ECEC setting by advancing their own understandings of objects and ownership, practicing their own ways of being with objects. Moreover, the results indicate that teachers’ contributions strongly influenced the outcomes of the encounters and, consequently, the constitution of shared understandings of objects and object ownership within the ECEC setting.

KEYWORDS:

• Early childhood education and care
• educational transitions
• infant-toddler
• video data
• spatial sociology
• social production of space

Introduction

During the transition from home to early childhood education and care (ECEC), for the first time, children are introduced to an institutional setting for care and education. Dalli (2003) suggests that during the transition from home care to ECEC, through peer interactions mediated by teachers, newcomers become aware of the possibilities and constraints the new environment offers. Teachers mediate peer interactions by accepting, ignoring or encouraging children’s actions towards peers, shaping the peer culture (Dalli 2003). To grasp the complexity of educational transitions that include not only the present time for those experiencing them but that are also embedded in institutions that precede and extend beyond individuals (Löw 2016), the current work utilises a spatial lens. Space is an interlinkage of symbolic and material components that is constantly under production, as it is (re)produced by actors in space (Lefebvre 1991; Löw 2016; Massey 2005). The present article explores how the ECEC setting as an institutional space is (re)produced within newcomers’ encounters with others during the period of transition from home care to ECEC. Here, negotiations of object ownership are discussed. Utilising encounters as a research unit directs attention to the interlinkages between context, actors, and action, supporting the exploration of children’s interactions in relation to the ECEC spatial orderings.

Young children’s first transition to an institutional setting

In the present research, a transition refers to a person’s move from one educational context to another (Fabian and Dunlop 2007) and is understood as a socio-spatial process (Lefebvre 1991; Löw 2016). Research on young children’s transition from home care to ECEC has mainly focused on infant-toddler’s attachment, stress, and negative emotions (Datler, Datler, and Funder 2010; 2012; Klette and Killén 2019; Nystad et al. 2021); some research emphasises children’s own experiences and perspectives of the transition (Dalli 2003; Dalli 2000; Simonsson 2015; Thyssen 2000; White et al. 2021). In Finland, studies focusing on infant-toddlers’ first months of attendance at an ECEC setting have addressed issues regarding children’s stress (Suhonen et al. 2018) and cry (Pursi and Lipponen 2021), infant-teacher interactions (Lucas Revilla et al. 2022) and mother-teacher trust (Rutanen and Laaksonen 2020), as well as daily transitions (Rutanen and Hännikäinen 2017). To broaden these perspectives, here infant-toddlers’ position within the ECEC setting during the transition period is discussed.

Space eventuates in the interlinkages of materiality and its symbolic meanings. The ECEC space encompasses ECEC practices, culture, and organisation, including the uses and organisation of material affordances and the built environment (Musatti and Mayer 2011; Raittila 2013; Raittila and Siippainen 2017; Syrjämäki et al. 2017). Institutional culture, its practices, and organisation are connected to larger socio-historical traditions (Tirri and Husu 2002) that are concretised in the institution’s goals (i.e. education and care) and values (EDUFI 2018; Johansson, Emilson, and Puroila 2018). Spatial sociology argues that institutions precede and extend beyond actors, constraining and directing action through shared cultural understandings (Lefebvre 1991; Löw 2016). Within institutional settings, such as ECEC, action is constrained by the established ways of doing things, norms, and power structures (Formosinho and Barros Araújo 2004; McNair 2022), which elaborate on ECEC practices, culture, and organisation, and thus, draw from socio-historical traditions, institutional goals, and values.

In this way, children’s voices and perspectives can be overpowered by teachers, norms, routines, and other institutional constraints (McNair 2022). Some have argued that, to gain access to the ECEC community, children must conform to norms, hence limiting their agency (Ree, Alvestad, and Johansson 2019). For example, if considering the ‘right use’ of materials, can puzzle pieces depicting vehicles be used as actual vehicles to drive and fly, or are these only to be used for completing the puzzle? (Salonen, Sevón, and Laakso 2020). The answer to this question depends on ECEC goals and values linked to conceptions of children and childhood (Rutanen and Hännikäinen 2019). Overall, research on young children’s participation within the ECEC setting suggests that children’s lives within institutions depend on the institutional emphasis given to individual needs and initiatives versus collective norms and routines (Lundkvist 2022; McNair 2022; Rutanen et al. 2014; Rutanen and Hännikäinen 2019; Salonen, Sevón, and Laakso 2020).

Social production of space

According to spatial sociology, space is constantly under production (Massey 2005). Spatial orderings, such as the ECEC setting, are socially constructed in the flow of things and time (Löw 2016), so they do not exist independently of actors (Lefebvre 1991). Space is produced within practices and interactions. Hence, practices reveal how the space is understood by actors (Massey 2005). Lefebvre’s (1991) spatial triad proposes that actors perceive, conceive, and experience the world around them according to their own socially mediated understandings. In doing so, the actors draw from and reshape cultural understandings, (re)producing spatial orderings.

Recent studies have discussed multiple ways in which young children (re)shape the ECEC setting’s culture, practices, and routines (Boldermo 2020; Pairman 2020; Rutanen 2007 Vuorisalo, Rutanen, and Raittila 2015). According to Rutanen (2007), young children contest adult attempts to constrain action possibilities within the ECEC setting by resisting adult expectations. In doing so, young children create counter-cultures and promote novel possibilities for action (Rutanen 2007). Likewise, Pairman (2020) finds that children using the entrance of the centre as a play space against teachers’ directives promoted the redefinition of the space’s meaning and norms regarding its allowed uses. Here the interlinkage between practices and interactions, materials, and symbolic meanings is scrutinised revealing similar as well as further ways in which newcomers (re)produce the ECEC setting.

Materials and methods

The research

The current research is part of a longitudinal study of early childhood education transitions: ‘Tracing children’s socio-spatial relations and lived experiences in early childhood education transitions’ (Trace in ECEC 2019–2023). The project seeks to better understand transitions and young children’s socio-spatial worlds during critical periods of transition (Lucas Revilla et al. 2022; Rutanen et al. 2018; Rutanen et al. 2021; Rutanen et al. 2022; Rutanen and Laaksonen 2020; White et al. 2020). The Trace in ECEC project is also part of a Finnish subproject building on a larger study across six countries: ‘ISSEET’ (Rutanen et al. 2016; White et al. 2022).

Aim and research question

This research has aimed to explore how ECEC institutional space is (re)produced within newcomers’ encounters with others during a period of transition from home care to ECEC. This broad aim has been achieved by exploring negotiations of object ownership in newcomers’ encounters with peers, mediated by teachers.

Data, procedure, and participants

This investigation draws on video-recorded ethnographic observations from three young children’s period of transition from home care to ECEC (three months). The Trace in ECEC project has collected data from five children (the cases), ages one through six, over a period of five years; the data cover multiple transitions. Three cases were selected based on the richness and length of video-recorded observations. Namely, the cases that featured a broader camera angle and greater number of recorded hours were selected. Utilising video-recorded naturalistic observations in the ECEC setting involves some challenges. Overall, the width and richness of the data are constrained by ethical constraints of video methods with young children (Peters et al. 2021), access to the field and participants (Rutanen et al. 2018), and challenges of long-term ethnographic research within educational settings (Eder and Corsaro 1999).

To capture the children’s transition process, data collection was spaced over time. The children, Leo (13 months), Jani (10 months) and Viola (18 months), were followed in their own ECEC settings during their first months of attendance. The selected data set was composed of 15 h of video from the children’s first three months of attendance. These data were collected at five collection points at the ECEC centres: on the first day of the child without the parents, after one week, and after one, two and three months of attendance. During each of these data collection days, 30 min to 2 h of short videos (1–15 min) were recorded. The videos centred on the newcomer activities and featured peers, teachers and the ECEC setting. From each data collection day, the videos included a variety of activities, such as drop off and pick up, breakfast and lunch, play (indoors and outdoors, individually, with teacher, and with peers) and routines (toilet, dressing up, sleeping). In addition, field notes and structured observations recording each day from arrival to departure were collected. These served as background information for the child’s day when clarifications were needed.

Ethical considerations

The Trace in ECEC project was prereviewed by the ethics committee of the University of Jyväskylä. All participants’ names are pseudonyms. Written informed consent was obtained from all participants. Children’s consent was sought from children’s guardians. In addition, children’s approval during the data collection was negotiated in situ; for instance, the researchers withdrew from the situation if it felt too invasive or lacked the children’s consent (see Rutanen et al. 2021).

Analysis

The analysis followed an inductive data-driven approach, drawing on video interaction analysis principles (Jordan and Henderson 1995; Pascale 2011). To begin with, the video-recorded ethnographic observations were sorted into units, that is, peer encounters. An encounter starts when (at least two) children make eye contact or when (at least two) children direct their gazes towards the other and perform actions connected to the other’s (without eye contact). An encounter lasts as long as children’s actions remain connected, which was assessed by paying attention to the children’s gaze. On many occasions, a teacher joined and/or mediated peer encounters. The encounters were written down in detail in chronological order. From the 15 h of video, 148 newcomers’ encounters were recorded.

Determining the beginning and end of an encounter was challenging. On some occasions, children focused momentarily on their own activity or directed their gaze at ‘what was going on’ around them before resuming the previous action connected to that of the peer. Therefore, the number of encounters was not important; rather, children’s activities within the setting are key. During the first months of attendance, young children moved a lot, going from activity to activity individually. Nonetheless, as they moved about the space and within activities, encounters with peers happened frequently. In other words, children frequently looked at each other, found each other’s gaze, and engaged in actions connected to those of peers.

Seeking to better understand how the institutional space was (re)produced within the newcomers’ encounters, material affordances were explored. Through analytic induction (Pascale 2011), the roles of objects, furniture, and structural elements (such as glass doors) were scrutinised. Similarities were sought within and across cases regarding the roles that material affordances played within the encounters (Pascale 2011). An in-depth exploration of these roles is outside the scope of the current article (see, e.g. Bateman and Church 2017; Puroila and Estola 2012; White et al. 2021; Sørenssen and Franck 2021). Encounters in which the participants took, retook, claimed, and protected an object (e.g. toys, clothing, sand, etc.) from others were selected for in-depth analysis. In these encounters, more than one child claimed the object, but only one kept it. Within these encounters, the objects acted as a pivot around which the participants’ actions revolved; moreover, the objects acted as a bridge between the child and setting, enabling children’s views and understandings to be visible to others.

According to video interaction analysis (Jordan and Henderson 1995), once a studied interaction has been identified and isolated in the body of data, the researcher should watch each data excerpt, focusing on contextual aspects and seeking patterns from the interaction’s context. Within the selected encounters, the catalyser of disputes and negotiations over objects seemed to be linked to the participants’ contrasting views regarding the object being free (to take) or owned (by someone). In relation to this, a series of spatial–temporal cues (Table 1) were identified by the researcher that could be connected to participants’ perceptions of the object as free or owned.

Table 1. Spatial-temporal cues indicating an object’s status.

Spatial	Temporal	Examples of participants interpretations of cues
The object is in a peer’s hand	The peer has the object right now	Object is free	Newcomer takes the object from the peer’s hand.
		Object is owned	Peer retakes the object taken from their hand.
The object is lying on the ground	The peer had the object recently. The object has been on the ground for a short time (Ex. 1. Lying on the ground doesn’t mean it is free)	Object is free	Newcomer takes the object from the ground.
		Object is owned	Peer claims the object taken by the newcomers, retakes it and protects it. The teacher supports the peer’s claim.
	The peer had the object before. The object has been on the ground for a long time (Ex.2. If it is lying on the ground, then it is free)	Object is free	Newcomer takes the object from the ground. The teacher supports the newcomer by protecting the object from peers on behalf of the newcomer.
		Object is owned	Peer tries to retake the object taken by the newcomer.

As exemplified in Table 1, the spatial–temporal cues were interpreted differently by teachers, peers (who have already been attending ECEC), and newcomers. Children took objects from peers’ hands as if they were free, and objects that were lying on the ground, apparently free, were claimed as owned by a child as soon as another child took them. The participants’ diverging perceptions of the objects and multiple ways of interpreting spatial–temporal cues led to negotiations of object ownership.

Two examples, one from Leo (13 months old) and one from Jani (10 months old), are discussed. The peers in the examples are one to three years old. Both teachers hold vocational (upper secondary level) qualifications in social welfare and healthcare (see Act on Early Childhood Education and Care, 540/2018). The examples complement each other when the teacher’s actions are the focus; in both examples, the disputed object is taken by the newcomer from the ground. However, in Example 1, the teacher supports the peer retaking, protecting, and keeping the object; while in Example 2, the teacher (a different teacher) supports the newcomer.

Results

Within the object ownership negotiations, the participants drew from spatial–temporal cues indicating whether an object is free or owned. Through a negotiation process in which the participants advanced their understanding of the objects and ownership by taking, claiming, retaking, and protecting the object, the ownership of the objects was determined. Within the negotiations, ECEC spatial orderings, norms, and shared understandings became visible and reproduced. At the same time, as participants perceived, interpreted, and negotiated, objects and object ownership, new shared understandings were created, producing the setting (a new).

Ex. 1. Lying on the ground doesn’t mean it is free

This example concerns Leo’s arrival on his first day. Leo has been in the centre for about two and a half hours.

I’m not done

The teacher, Leo and two peers are in the corridor. The teacher is removing outdoor clothes from the children one by one while the other two wait. Leo is the first one ready. He is exploring the materials sitting next to the teacher. As the teacher undresses Lisa, she removes a wooden toy dog that was next to Lisa’s feet and puts it on the other side in front of Leo. Leo takes it. Lisa vocalises. Leo looks at Lisa and nods. Lisa vocalises again. When the teacher finishes undressing her, Lisa takes the toy from Leo and says ‘me, me’ (‘minä, minä’ in Finnish). They tussle over the toy. The teacher intervenes, suggests sharing, but immediately corrects herself and says ‘No!’, gives Leo a book and the dog to Lisa. Leo tries to get the dog again. Lisa complains with her voice. The teacher gives Leo a duck, but Leo continues to pursue the dog. Leo takes the dog, Lisa complains, takes it back, gives him the duck and moves a bit away from Leo. Leo reaches for the dog again. She takes it and goes further away. Leo waits for a moment and then follows Lisa and tries to take the dog. Lisa complains and tries to go away. Leo grabs her. She complains and runs to the teacher. The teacher verbalises the situation: ‘Is Leo trying to take the dog?’ Leo doesn’t try to take the dog near the teacher. Leo goes on to explore other things. After a moment, the teacher finishes undressing Kameron, the third peer. Kameron tries to take Lisa’s dog. They have vocal arguments. Leo grabs Kameron. The teacher verbally intervenes; they stop. The teacher tells Kameron to take the duck. Lisa approves and says, ‘Duck’. Leo goes to check a book. Kameron is upset, saying he wants the dog. The teacher tells him that it is Lisa’s turn. Lisa gives him the duck and takes the dog with her to the other room.

In this example, the spatial cues (see Table 1) that may indicate ownership are: the object is first next to Lisa’s feet before being placed on the ground apparently unattended in front on Leo. The temporal cues (see Table 1) regard Lisa having had the object recently, which is elaborated into the concept of turn; the object was lying on the ground apparently unattended for a short moment. Leo perceives Lisa’s dog as free and takes it. Lisa and the teacher perceive it as owned by Lisa. Lisa claims, retakes, protects, and keeps the dog. The teacher supports Lisa by utilising speech in the form of direct orders and mediating strategies. The teacher asserts that it is Lisa’s turn, justifying her position; she seems to draw from cues regarding the initial position of the dog, near Lisa’s feet, Lisa having had the dog recently and the object having been on the ground just for a short moment as indicating Lisa owning the dog. As the negotiation advances, new cues appear; for example, the teacher supporting Lisa’s claim could be seen as a social cue. Moreover, Leo’s contrasting views and repeated attempts of taking the dog against the teacher’s directives may have opened up the space for negotiation, offering an opportunity for Kameron to challenge the teacher too.

Ex.2. If it is lying on the ground, then it is free

This example, extracted by transcribing the video, is taken from Jani’s outdoor play time. Jani has attended the centre for two weeks.

It is mine

A group of four children and a teacher are playing outdoors in the yard’s sandbox. With a truck, Simo returns to the sandbox from a brief visit to the other side of the yard. He shows Jani the truck. Simo plays for a few minutes with the truck, using it as a scoop for filling a bucket with sand, then leaves the truck next to him and continues with his hands. Fifteen minutes later, Jani takes the truck from the ground in front of him. As Jani picks up the truck, the teacher tells him not to put it in his mouth. Simo, who is behind Jani, stretches himself and looks over Jani’s shoulder to see what is that he has in his hand. Simo sees the truck and tries to take it from Jani’s hand. The teacher stops him. Maila, who is seating near Jani over at his side, takes the truck from his hand. The teacher tells her to give it back. Maila gives it back. Jani starts playing with it. Both Simo and Maila stare at Jani playing for a moment; then, they resume playing as they were with buckets and sand.

In this example, the spatial–temporal cues (see Table 1) that may indicate ownership regard the object’s physical position on the ground near Simo, as well as Simo having owned the object before. The object has been laying on the ground for 15 min. Jani perceives the truck as free and takes it. Simo and Maila perceive the truck as owned by Simo or at least not owned by Jani. The peers try to retake it from Jani’s hand. As in the previous example, Simo draws from cues that could be elaborated into the concept of turn, such as having brought the truck to the sandbox and having had it before. However, the teacher perceives the truck as free, possibly drawing from cues regarding the object’s position (being on the ground) in relation to time (for a long period of time). The teacher helps Jani keep the object, protecting it with her body and using direct orders to prevent Simo and Maila from retaking it. Jani and Simo have contrasting ways of perceiving the object and understanding the spatial–temporal cues, giving place to a negotiation. Jani is aware that Simo had the truck first and that he brought it to the sandbox because Simo showed Jani the truck. However, for Jani, the object was already free while Simo perceived it as still owned. In this case, Jani’s understanding is reinforced by the teacher. However, it is possible that Simo’s contrasting way of understanding the object’s ownership forwarded an opportunity for Maila to challenge the teacher’s directives.

Discussion

In their encounters with others, by advancing their own ways of perceiving objects and objects’ ownership, newcomers promoted object ownership negotiations. Within the negotiations, the participants’ own interpretations of spatial–temporal cues (see Table 1), objects, and objects’ ownership revealed, and (re)produced the ECEC setting. The setting was revealed and reproduced in aspects such as teachers’ decisive power to determine ownership and command children’s actions, objects being treated as jointly owned (Puroila and Estola 2012), which was elaborated through the concept of turn, the upholding of norms of conduct such as children not being allowed to take objects from peers’ hands, and overall, within participants’ interpretations of spatial–temporal cues which were context specific.

In addition, the setting was produced (a new). Participants created new shared understandings. Within the negotiations, some ways of understanding the object and its ownership were successful, affording the holder ownership of the object, while others failed. By instance, carrying an object to a new location may now be understood as not granting ownership if the object has afterwards been left unattended for a long period of time on the ground. Hence, as Dalli (2003) proposes, the teachers may have shaped peer culture by accepting or rejecting children’s actions; however, as discussed by Rutanen (2007), children may have created counter-cultures by resisting adults’ expectations. In this way, participants created new shared understandings that include both prevalent ECEC practices and culture, as well as children’s initiatives and views.

The objects acted as a window into the symbolic meanings of the setting, offering concrete opportunities for the children to act upon the setting, testing and constructing their own socio-spatial understandings (Rutanen 2007; White et al. 2021; Simonsson 2015). Within Finnish ECEC, material resources are conceptualised as jointly owned, which, in combination with the finite availability of resources, constrains children’s access to desired or preferred resources, leading to frequent ownership negotiations and disputes (Puroila and Estola 2012). Moreover, by picking up an object off the ground, children may not only want to gain control of the object but may be trying to access and join peers’ play (Singer and Hännikäinen 2002). Likewise, overly restricting peers’ access to an ‘owned’ object may drive them away during joint play (Aarsand and Sørenssen 2021), making object ownership an intricate matter, encompassing social, cultural, and spatial cues to be shared, (re)defined, and learned by young children during their transition to ECEC.

Transitions are often conceptualised as sociocultural processes (Fabian and Dunlop 2007; Dockett, Petriwskyj, and Perry 2014; Pianta and Cox 1999; Kagan and Tarrant 2010). However, spatial sociology argues that, shaped by culturally mediated understandings, actors (re)produce space as they make sense of the world around them, reshaping culture in the process (Lefebvre 1991). Thus, the ECEC setting’s practices and culture are (re)produced in the flow of things and time (Löw 2016) as actors make sense of and give meaning to the setting (Rutanen 2014). Thus, transitions can be seen as socio-spatial processes in which the ECEC setting is reorganised and reshaped (Raittila and Vuorisalo 2021; Vuorisalo, Rutanen, and Raittila 2015). For the ECEC setting, newcomers bring new opportunities to develop institutional practices by offering new perspectives and challenging what others may consider obvious or take for granted (Aarsand and Sørenssen 2021).

Nonetheless, newcomers’ encounters during transitions are embedded within the ECEC setting and, thus, inseparable from existing practices, the ECEC organisation, its material affordances, and its built environment. Delivered through power structures, institutions constrain and direct action by enforcing shared cultural understandings, concretised in established practices and norms (Lefebvre 1991; Löw 2016; McNair 2022; Formosinho and Barros Araújo 2004; Ree, Alvestad, and Johansson 2019). Overall, negotiations are a prevalent ECEC practice that allows children to resist the institutional order and exert power (Singer and Hännikäinen 2002; Salonen et al. 2022). Through negotiations culture and practices are agreed upon, shared, and (re)shaped (Boldermo 2020; Rutanen 2007; Aarsand and Sørenssen 2021; Puroila and Estola 2012). In ECEC, teachers employ mediating and high-power strategies to mediate negotiations that include disputes. Mediating strategies involve proposing alternatives to children and working with the children’s own ways of handling a dispute, which allows for and promotes negotiations. High-power strategies, on the other hand, involve giving directives and reminding of rules, possibly aggravating the dispute and ignoring the children’s perspectives (Singer and Hännikäinen 2002).

Within the discussed examples, the teachers’ use of high-power strategies may be linked to the teachers’ perceptions of newcomers as needing support. In the first example, the teacher uses mainly mediating strategies, which may indicate that she considers (or knew) that Lisa possesses strategies to protect her object and handle the dispute. In the second example, the teacher acts in the name of the newcomer, employing high-power strategies, solving the dispute in her own terms. In addition, in the first example, the teacher uses strict directives towards the newcomer. Overall, these aspects may indicate that newcomers may be perceived by teachers as lacking dispute-solving strategies, which may limit newcomers’ opportunities to influence negotiations that include disputes.

The current research contributes to a relational understanding of young children’s encounters, transitions, and ECEC setting, discussing the (re)production of space through negotiations. Space is an ongoing practice interwoven with time, always being made (Löw 2016). Children co-construct the ECEC setting through their negotiations with others (Boldermo 2020; Rutanen 2007). Moreover, disputes are a powerful aspect of negotiations that make participants’ views visible and the negotiation meaningful, offering key opportunities to share, co-construct, and reshape everybody’s understandings (Singer and Hännikäinen 2002). This research calls for practitioners to pay attention to and rely on children’s understandings of ‘what is going on’ to teach and foster fairness and to forward practices that promote children’s agency (Salonen et al. 2022). It is not always easy to access and understand children’s views; however, the present research suggests that children’s claims and views are founded and trustworthy and, thus, should be taken into consideration as such.

Limitations

The discussion presented is not aimed at being generalised to all cultures and institutional settings. Moreover, teachers’ roles and ways of positioning themselves are connected to the particular encounters discussed. On the one hand, teachers seek to resolve disputes as quickly as possible (Singer and Hännikäinen 2002), and on the other hand, they may be more vigilant when newcomers are involved; therefore, within different types of encounters, diverse teachers’ positions and roles will appear. Finally, encounters have been selected as a unit of analysis and defined as clearly as possible; nevertheless, determining the beginning and the end of an encounter remained challenging. Encounters as research tools have great potential to support research that better depicts young children’s lives within peer groups; further research that elaborates encounters is encouraged.

Acknowledgements

The authors wish to thank the children, families and ECEC settings that participated in this study, as well as the students’ and assistants’ participation in data collection.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the [Research Council of Finland]; [Otto A. Malm foundation]; and [University of Jyväskylä].