Maroni Clémence Léobal

Transborder Dwelling in Albina (Suriname) and Saint-Laurent (French Guiana) on the Lower

This chapter focuses on daily life in twin cities spanning a European border, where the same living space (the Maroni river) became administratively separated at the time of Suriname's independence in 1975. Its approach is to look more specifically at the concrete and daily implications of life in twin cities for the Ndjuka working-class inhabitants, and their perception and experience. Forms of transnationalism at a local scale also involve kinship relations. Building on Marcelin's concept of "configuration of houses", this analysis is based on a ethnographic case-study of one large family who lives on both sides and show how they dealt with the political border and how the border affected them. First, I describe this group's conceptualization of living on the border in a configuration of houses straddling both sides. I then explore the circumstances, both private and administrative, forcing on of its female member to return to her maternal family on the Surinamese side. Finally, I examine the experiences of this woman and other border inhabitants facing the complex entanglement of State administration policies on houses, healthcare, social benefits and land-access.

Bio

Clémence Léobal is a sociologist, permanent member of the French National Center for Scientific Research. She belongs to the Lavue (Nanterre University). Her work on French Guiana began in 2009, when she was employed by the Saint-Laurent-du-Maroni town hall to prepare its

Until very recently, the Maroni River was a porous border between French Guiana and Suriname, a now-independent former Dutch colony. Like many post-imperial Caribbean borderlands, this porosity existed despite the authorities' best efforts at immigration and commercial-exchange control. However, in March 2020, the global COVID-19 pandemic succeeded where French authorities had failed, closing the border for the first time in its history. In March 2020, Surinamese authorities imposed a near-total ban on Albina-to-Saint-Laurent pirogue crossings (wooden boats).

As of June 2020, this has caused major food shortages on the French Guianese riverside and mass unemployment on the Surinamese side.

Before closure, local populations both crossed the river and also inhabited its banks and islands. As such, according to the habiter concept, meaning activity of building a territory in the world [START_REF] Hoyaux | Entre construction territoriale et constitution ontologique de l'habitant: Introduction épistémologique aux apports de la phénoménologie au concept d'habiter[END_REF], they were creating an intimate relationship with opposite places. Situated on the Maroni estuary, the twin towns of Saint-Laurent-du-Maroni and Albina are inhabited by people who continually crossed this 5 kilometres-wide river. The Ndyuka are one of the Maroon groups that fled (and fought) Suriname plantation-owners. Nowadays, they say they 'wear' French or Surinamese nationality, meanwhile identifying as Ndyuka, an independently conceptualized identity connected to territories upriver where the Dutch Republic through the 1762 peace treaty recognised their sovereignty. The Maroni Basin is populated by Amerindians and Maroons, both of whom resisted colonialism and lived largely autonomously from their respective State governments [START_REF] Piantoni | L'enjeu migratoire en Guyane française: une géographie politique, Ibis rouge[END_REF]. In recent decades, these ethnic groups have undergone profound social transformations due to mass migration to towns along the river. Maroon ethnic groups have created a transborder territory along this political border; characterized by the omnipresence of the two 'sides', sharing a common language (Migge and [START_REF] Léglise | Language and identity construction on the French Guiana-Suriname border[END_REF]. The Ndyuka concept of liba means both 'river' and 'inhabited territory'. The river is thus considered less a division than a link between two banks. While the Ndyuka (among Maroon and Amerindian groups) inhabit both banks, the administrative border linking them separates a European country (French Guiana is part of France) from Suriname, an independent Third-World republic.

The Maroni border is 525 kilometres long, and contested by Suriname in the upriver zones.

Immigration rules applying here are based on French law but much stricter than those in metropolitan France: there are many derogations reinforcing immigration-control [START_REF] Benoît | Sans-papiers amérindiens et noirs marrons en Guyane: la fabrication de l'étranger sur le fleuve Maroni[END_REF].

However, the rules have very low effectivity due to high cross-border mobility. The Police aux Frontières certainly do not check all boats crossing the river. Since 1985, the official border-post has been located in Iracoubo, 110 kilometres up the Saint-Laurent-to-Cayenne road.

Transborder ways of dwelling are broadly shared among all those on the estuary, including the working classes, Maroons, Kali'na Amerindians [START_REF] Collomb | Setting up Frontiers, Crossing the Border: The Making of Kari'na Tyrewuju[END_REF]Renault-Lescure, 2014), Haitians (Laethier, 2014), Brazilians [START_REF] Heemskerk | Moving frontiers in the Amazon: Brazilian small-scale gold miners in Suriname[END_REF] and the local transnational elite (Chinese traders and Surinamese entrepreneurs). I focus on these towns' day-to-day life, where common living-space became administratively separated upon Surinamese independence in 1975, examining the concrete, day-to-day implications of living there for Ndyuka working-class inhabitants along with their perceptions and experiences. At local level, transnationalism [START_REF] Schiller | Transnationalism: A New Analytic Framework for Understanding Migration[END_REF] involves borderlanders' pride in being able to navigate between Suriname and French Guyane, but also ethnic pride to be Maroon. It involves kinship relations as well. Inhabiting the Maroni thus entails ways of dwelling within larger kinship groups, involving solidarity but also tensions, power relations, conflict and dysfunction. In her study of the Mexican-US border, Whiteford invented the concept of 'extended community' to analyse how kinship networks transcended barbed wire [START_REF] Whiteford | The borderland as an extended community[END_REF]. Here, I draw on this but also build on Marcelin's concept [START_REF] Marcelin | L'invention de la famille afro-américaine: famille, parenté et domesticité parmi les Noirs du Recôncavo da Bahia, Brésil[END_REF], where people do not live just in single houses but multiple houses. Connecting kinship anthropology and residential geography, it helped analyse local ways of border-negotiation. The concept was associated with mobility, circulations and tensions [START_REF] Motta | Houses and economy in the favela[END_REF] and included governing modes that were both private (governing the house) and public (border policies). These configurations were shaped by familial conflicts involving class and national divisions intertwined with border policies. This analysis is based on a case-study of one large family I met in Saint-Laurent-du-Maroni, the largest town on the French Guianese side. This family group had also built a small village on the Surinamese side, close to the twin town of Albina. I will show how they dealt with the political border and how the border affected them. Their residential choices were underpinned by administrative opportunities and constraints. I conducted an ethnographic study in 2013/14, following one family member, Lena, through her various displacements and pursuit of official documents.

First, I describe this group's conceptualization of living on the border in a configuration of houses straddling both sides. I then explore the circumstances, both private and administrative, forcing Lena to return to her maternal family on the Surinamese side. Finally, I examine the experiences of Lena and other border inhabitants facing the complex entanglement of State administration policies on houses, healthcare, social benefits and land-access.

'Eating from Both Lands': Transnational Lives

'If the State demolishes my house, I'll build a stilt house on the river'. These were the words of Lili, a female elder living in Saint-Laurent-du-Maroni. Her house was threatened with demolition because the French Guianese authorities considered it illegal. Lili had no building permit, no title-deed or land-tenure, no personal authorization to live on French territory. Beyond her proposal's humorous overtones (stilt dwellings are no longer constructed in the town), she underscored her conceptualization of inhabiting the border with her projection 'on the river'.

I first went to Lebi Doti, a peripheral neighbourhood, to visit Lili's niece-in-law, Lena, a 25-year-old Ndyuka woman. I had made contact through Diane Vernon, an anthropologist working in the local hospital culturally mediating between patients and medical staff. She introduced me to Lena, who lived in a sector set for demolition. Lena regularly visited the hospital because of her disabled child.

Lena was being accommodated by Lili, her husband's aunt, and they lived with many relatives in two houses. Over frequent visits, I came to understand that Lena occupied a marginalized position among them. A year later, she moved back to the Surinamese bank due to familial pressure alongside the administrative deadlock she faced as an undocumented person.

Although telling her many times I was not working for either local administration but for a Paris university, Lena expected me to help her secure social housing and residence-documents, seeing me as a White (bakaa) woman somehow connected with the State. I felt guilty being unable to help more. The little I could provide for these inhabitants (e.g., occasionally purchasing food and medicines) was incommensurate with the invaluable thoughts they shared on border life during our afternoon discussions.

Lili had spent her whole life on one or other riverside. She never called this space a border, referring instead to its 'two sides'. One afternoon, as we sat on her terrace with her sister, she said, laughing: 'I'm eating from both lands'. This expression normally justifies male polygamy: 'eating from' different women. Lili, a widow, had taken it from its gender-relations context: inversing the implied power-relation, rendering herself superior in this two-sided territory, enjoying both lands simultaneously like polygamous Maroon men. This reveals her sense of belonging and mastery within the Maroni-River territory, much greater than the simple boundary depicted in State cartography (see figure 1).

Mapping the Border

Based on cognitive mapping (Aberley, 1993), these drawings spatially represent elements from my ethnographic research. The handmade representation underlines the constructional nature of any cartography. My drawings, do not attempt precise topography, though respectful of approximate kilometric scales. I forego the conventional northerly orientation of maps, instead orienting upriver, respecting inhabitants' perceptions conceiving places according to their river location. In the Ndyuka language, people either go upriver (opusey) or downriver (bilo).

Living Together in Several Houses

Lebi Doti was reached by a lateritic path called Piste des Vampires. Winding through dense vegetation, this path was not exactly an urban landscape. Lena and Lili lived in two houses perched on a hilltop. This 'hill' was actually an earth-mound bequeathed by a development company's bulldozers, which were already levelling the ground for three-storey buildings. The two wooden houses were divided into four homes. Franz lived in one house with his wife and ten children. The other was partitioned into three homes for Lili, Lena (plus husband and three children) and one of Lili's nephews' wives.

According to Marcelin, within such a configuration, the houses' inhabitants engage in relations comprising exchanges of goods and services. They can eat, sleep, circulate and leave children to be looked after within each other's houses. These configurations nevertheless can be changed by life events and conflicts within the group. Lena was dwelling together with other people. There were many exchanges between the four homes. Children circulated from one to another hoping to be fed whenever dishes were prepared. All the women would periodically care for each other's children, especially Lena's third child, Gabriella, whose illness rendered her insensitive to pain. Lena was often without resources because neither she nor husband Bobby had residence documents or received state benefits. In using the terms 'husband', 'wife' or 'marriage' here, I refer to a nonadministrative Ndyuka union, contracted in a ceremony between the couple's respective matrilineages. Bobby sometimes worked a 'job' driving someone's boat or building a house. Lili sometimes gave Lena a little of what she needed to feed her children. Franz and his wife also gave her products from their fields. However, this mutual assistance had limits. Lena had to go to community services that distributed food, mostly macaroni (which she hated). She could not count solely on neighbours' help.

Configurations of Houses across Urban and National Borders

Lena actually lived within two distinct configurations, her husband's in Lebi Doti and those of maternal relatives. Both extended across urban boundaries into other neighbourhoods and over the River.

Lebi Doti's inhabitants also lived closely connected with other houses in the town. They often visited Ine, Lili's sister and Lena's mother-in-law. She lived on the Piste des Vampires's opposite side. One of Lena's daughters took me there on my first visit, leading me along a winding path. Just 5 years old, she was used to going to see her grandmother by herself without asking permission, showing how often Ine looked after her. The extensive exchanges between Ine and Lili also resulted from past cohabitation. A few years before, after separating from her husband, Ine had lived at her sister's until one of Lili's friends 'gave' Ine some land so she could build a house -even though, as with Lebi Doti and most of the rest of French Guiana, the land was legally French State property.

When I returned to the field a year later, Lili was unwell and being accommodated and looked after by Ine. One of Ine's daughters had replaced Lily in her former house in Lebi Doti. The houses' occupants thus frequently moved in and out depending on life events (see Figure 2). This changing configuration resulted from changing relationships. Lena and Bobby had come to Lebi Doti in 2011, replacing one of Lili's other nieces, Kiki. Bobby had lived there with Lili as a young boy. The present configuration thus resulted partly from past arrangements. [START_REF] Vernon | Les représentations du corps chez les Noirs marrons Ndyuka du Surinam et de la Guyane française[END_REF]. Silvia lived in an individual State-owned house, which she had extended to accommodate several homes. Lena and Bobby visited several times weekly, for example to charge their phones: Lebi Doti being without electricity. The relatives had also gathered at Silvia's house when Lena's disabled child died in July 2013. During family crises, Lena also visited another estate further away called Charbonnière to see Silvia's sister, Mora. When Mora's daughter Amalia was hospitalised following a miscarriage, Lena visited her several times. Lena thus certainly lived in a configuration of houses: indeed, as I later discovered, moving back and forth between two configurations, that of Bobby's relatives, including Lili, Franz and Ine, and that of her foster mother's relatives. These configurations extended not only over urban boundaries but also over the national border.

Lili, Lena and her relatives had houses in a village across the river called Midina kampu. When I visited, both women spoke fondly of this village, describing it as a peaceful place with a beautiful creek to bathe in. Both had lived there, Lili in her own kampu very close to the current Midina kampu, until the Surinamese 1986 civil war destroyed it. She said 'the war dispersed the house', meaning everyone had gone their own ways. She subsequently moved to the French side, and her sister Ine moved to Paramaribo. . Lena and Lili lived closely connected with the surviving Midina kampu, which was included in their configuration. Lena visited the kampu very regularly. Her Tante had a house there as well as in Paramaribo. Many of the Tante's children had houses in the kampu, including Silvia and Mora, who also had social-housing accommodation in Saint-Laurent. The kampu inhabitants regularly came to Saint-Laurent, only thirty minutes away by boat. The kampu was also linked to Albina by a muddy track. The fifteen-minute taxi-ride from the kampu to Albina cost twenty euros, and the five-minute boat trip from Albina to Saint-Laurent three euros. A man once came from the kampu to Lebi Doti in his boat to deliver his sisters to the hospital to look after Amalia, who had miscarried. Their modes of dwelling thus involved solidary exchanges between houses from both sides of the river. This family group was appropriating this transborder space. Some like Lena's Tante, had multiple residences (see fig. 3, which reflects the situation during my research and especially from Lena's viewpoint). Mora and Silvia had houses in the kampu and on the French side, where their children attended school. They came to the kampu for holidays and weekends to relax or work in the fields.

Both Surinamese and French mobile-phone networks were available in the lower Maroni region facilitating cross-river integration. Most people had two phones enabling calls in either French Guiana or Suriname. for Lena to obtain residence documents. Furthermore internal pressures within the configuration placed many demands on Lena regarding her financial autonomy, motherhood skills and general respectability. These family-group tensions were unspoken in my presence. Only during the crisis triggered by Lena's child dying were they expressed aloud. They were nevertheless constitutive of the housing configurations. Mutual assistance and solidarity entail individual costs [START_REF] Gollac | Maisonnée et cause commune: une prise en charge familiale' in Gramain, A &Weber, F, Charges de famille[END_REF], even accompanying forms of 'tyranny' [START_REF] Douglas | The Idea of Home: A Kind of Space[END_REF]. Lena was doubly excluded, from Lili's configuration and from the French riverbank. This distinction was difficult to perceive because of an earlier alliance between these two groups.

Lena's Tante had been married to Lili's maternal uncle. Hence, all members of both configurations where Lena lived were inter-related. This alliance explains how Bobby, Ine's son, was raised by his great-uncle in the kampu, where he met Lena. Lili had not returned to that side of the river since the war, but still had relatives there. Lena was raised by her Tante, to-ing and fro-ing between her houses in the kampu and Paramaribo. This was how Lena met her two husbands. She had first come to Saint-Laurent in 2003 to have her eldest daughter treated at the hospital (she died a few years before I met Lena). When her third daughter, Gabriella, began suffering the same illness, Lena's relatives held her responsible, believing her a bad mother, too lazy to work or get her residence documents. Diane Vernon told me later Lena was held responsible for her child's illness because her first husband was a maternal cousin, strongly prohibited by Ndyuka custom. Its death was interpreted as ancestral punishment.

Lena's childcare practices shocked me. I thought I was being normative but later realized her family also believed her a poor mother. Thus I felt disgusted by seeing how Gabriella generally spent the whole day dirty because of dust from their house's dirt floor in Lebi Doti. A nurse visiting them regularly had recommended Lena putting socks on Gabriella's hands to prevent her biting them and consequent infection, but the socks were dirty. The way Lena treated her five-year-old eldest daughter, Gabi, also horrified me. Lena constantly and peremptorily asked her to do domestic chores, like caring for the younger children or buying provisions from neighbours. Gabi had not yet attended school and I felt she should do so because teachers told me how crucial nursery school was for French-Guianese children to learn French.

Over the months, I discovered that many relatives also criticized Lena and felt she was overdependent. These criticisms only surfaced after Gabriella's death. I went to Silvia's house, where everyone gathered in mourning. Lena sat in the living room, wearing black-and-white mourning clothes, surrounded by many relatives, including Silvia and Mora. Lena told me her daughter had undergone surgery when her hand became infected, and never awoke. I immediately thought there had been a medical error. However, Lili and Franz's wife provided a different version when I visited them later. They claimed it was Lena's fault because she should have entrusted Gabriella to the State (meaning the children' hospital).

Upon returning to the field a year later, I visited Lena at Midina kampu. She had returned to her Tante's configuration after exclusion from Lili's. Lena rejected Lili's and Franz's accusations: 'They say I killed her, but it was the doctor's fault'. She suggested Franz refused to drive her to the hospital that night, saying she was always bothering him for something. She found a taxi instead.

The lack of support from members of her previous configuration was why she had returned to 'her' family in the kampu,. She added she had not entrusted Gabriella to the doctors because they took her first child to Martinique without her permission, where he died, and she could not bury him. She had not wanted that happening again.

However, Lena's support within her Tante's configuration was also limited. Neither Mora nor Silvia had offered accommodation in Saint-Laurent. Her Tante provisionally lent her half a house to stay in with her husband and their children. However, she had to prove willingness to become financially independent. Her husband found a security-guard job in one of Albina's Chinese shops, and she started planting a field near the kampu. She also planned to build a house. Silvia would give her some land she had bought nearby, between the kampu and Albina. Lena was, however, Silvia's second choice; Silvia had wanted to give it to her own daughter, but she already had a house in Saint-Laurent. This shows Lena's marginality within her Tante's configuration. The two river-banks did not share the same status in this transborder configuration. Although living on the French side meant enhanced social-benefit access, Lena had to return to the Surinamese side because of her marginality.

The border territory had two unequal sides. This was clear from people's everyday journeys to different institutions. Lena never considered her move beyond the border permanent. After my kampu visit she crossed to the French side several times visiting relatives or government offices.

Her disabled child's death had reduced her chances of getting her residence documents because the hospital's social workers had been supporting her regularization application. However, she still hoped to return to French Guiana. Her eldest daughter, Gabi, was still being schooled there even though she had moved to the kampu. At first, she had entrusted Gabi to a sissa in Saint-Laurent who eventually threw the little girl onto the street, where the police found her. During my visit, Gabi was staying at someone else's house in Albina so she could cross the river every morning for school in French Guiana. A schooling certificate can serve as proof in regularization applications that someone has stayed five years or more on French territory. Lena had not totally relinquished the idea of living on the French-Guianese side.

National Lines and Urban Planning: Facing Eviction.

The border also became concrete in Lebi Doti's inhabitants' everyday lives through the denial of land rights. In 2011, French authorities had demolished their fields, asking them to leave. For a long time, urban planners had failed to take into account the presence of many existing residents in designing a huge project for 4,000 social-housing dwellings. Also in 2011, an NGO commissioned a study of 'spontaneous dwellings' in the zone. Helped by aerial images, the authors estimated over 6,000 people lived in the zone and surrounding areas (DEAL Guyane, 2012). The project's implementation implied their eviction. Demolition had occurred at the site where the first buildings were being constructed. During initial groundworks, the project's building company -the Senog, Société d'Economie Mixte de l'Ouest Guyane, which is 80% municipally owned -had instructed bulldozer drivers to dig very close to existing dwellings aiming to intimidate residents into leaving.

Those with French citizenship or French-residence documents were sometimes offered social housing. 'Illegal' immigrants, however, had no right to social housing. Intimidation mostly worked.

In 2013, only a few houses remained amidst a flattened space, including Lili's.

Lili described the bulldozer arriving, their crops being destroyed and how she looked on helplessly. She denounced the injustice of demolition, comparing the country with Suriname, where this would never happen: 'they give you the land, and they cannot demolish your work'. Her son Franz was fighting the clearance, using French law to demonstrate his goodwill and good faith. They showed me photos Franz had taken upon learning his field would be destroyed. Franz recalled the same thing happened when the municipality evicted them from a neighbourhood called Vietnam transferring them to Djakata. The mayor had not come himself but sent his son, as municipal representative, along with his colleagues. This time, however, Franz believed he was well within his rights. In Vietnam, many people were occupying the land, but here he had gone through the official procedure to apply to the French Guiana public development agency (EPAG) for the title deed. This procedure was uncompleted, but he had retained the application receipt, which he showed me proving his goodwill even though he knew it did not constitute a title deed:

When I saw the place, before I cleared it, I went to the EPAG. The agents looked at the map and said, this land belongs to state property, so if I want it, what do I want to do with it? I said I wanted to cultivate the land and build a house, I wanted to live there. They said OK.

They gave me a form, I filled it out and sent it. Then I received this receipt. This meant I had to wait a little while.

Franz was illiterate, but knew exactly what the procedure meant. He had recently obtained French nationality having been stateless his whole life -he was born on his mother's kampu, never being registered by any State. In 2011, he had tried to go to the tax office to pay the land tax, like his neighbours' to prove occupation, but was told he should have done so long before because it was now impossible with the planned urban-development project.

Franz claimed he knew nothing about the project before 2011, protesting the injustice he was subject to. He argued the EPAG was willing to give him the land but the commune's mayor blocked it: certainly all EPAG land-applications were first unofficially municipally reviewed. He was angry about other Ndyuka people coming to settle on 'his' land without his authorization. Upon seeing the workers demolishing his field, he visited the mayor's son, whom he knew personally. The latter said Franz could receive compensation for his fruit trees and EPAG officials had been sent to count them. Franz saw them but did not know they would destroy everything. He had to accept this meagre consolation and return home. Nevertheless, he continued defending his rights using the register of French administrative law. He was thus arguing (on behalf of his group) their defence in French legal terms even though judicial success appeared slim. French-Guianese power-structures made this procedure nearly impossible: working-class Maroons were marginalized by State officials applying French law in ways providing no chance of winning their right to their land. Franz's action just left Lebi Doti people in a wait-and-see situation, withstanding threat of demolition thanks to their own resources and agriculture. Six years later, Franz was still there, surrounded by new buildings and awaiting a deal to legalize his situation.

***

In these twin cross-river, cross-border towns, Ndyuka inhabitants negotiated a combination of State opportunities and constraints. They had created a transborder space, connecting Saint-Laurent and Albina, where national hierarchies were in play. The two sides did not have the same value.

Compared with Suriname, French Guiana offered the Ndyuka more healthcare, benefits and housing-prospects, but also greater risks around residence documents and denial of land-rights.

National borders and social boundaries intertwined with kinship groups. Ndyuka people did not just inhabit single houses but entire configurations, where residents actively engaged with each other based on matriliny. While exchanges and solidarity were evidenced between the evolving housing networks, these ways of dwelling were also structured by tensions. Lena's story shows that belonging to a configuration entailed individual costs. People had to follow certain rules, like proving they would try to become financially independent or be good parents. If someone transgressed, they could be excluded or marginalized. However, in the case of evictions, for example, kinship-ties allowed mobility to the Surinamese side of the river and the capacity to return depending on administrative constraints. These configurations thus provided solidarity resources helping Ndyuka people cope with State constraints.

Figure 1 :

 1 Figure 1: Lili's trajectory through civil war. Source: Map by Clémence Léobal.

Figure 2 :

 2 Figure 2: Lena's kinship tree Source: Drawing by Clémence Léobal

Figure 3 :

 3 Figure 3: Lena's transborder configuration of houses and trajectory Source: Map by Clémence Léobal

I

  understood the distinction between Lili's and Lena's Tante's side only after Lena's child died at the end of my first fieldwork-stay in July 2013: when I returned after the ensuing crisis in 2014 I noticed Lena had moved from Lebi Doti to her Tante's in Midina kampu. The configuration of houses, including Mora's, Silvia's and Lena's, was reproduced on a different scale here. One entire neighbourhood of the kampu constituted what they called Lena's Tante's Ma bee: bee meaning 'belly' also refers to the 'lineage' or the neighborhood formed by a Ma (woman) and her descendants. Her house stood amidst an array of houses belonging to her children and other relatives. Mora and Silvia thus supported Lena in Saint-Laurent because of their common relationship to Tante's as attested by the layout of the houses in Midina kampu. Lili and her relatives had supported Lena because she was Bobby's wife.

Center for the Interpretation of Architecture and Heritage. concrete consistency through the diversity of the administrative network and its uses on the Maroni.


Helena Mentis
email: helena.mentis@umbc.com

Aaron Quigley
email: aquigley@st-andrews.ac.uk

Philippe Palanque
email: palanque@irit.frv

The Evolution of SIGCHI Conferences and the Future of CHI in Africa in 2008 (DIS '08 in Cape Town). We have further provided in-cooperation support to 427 conferences, of which 91 have been in North America, 231 in Europe, 53 in Asia, 25 in Oceania, 19 in South America, and eight in Africa.

Not surprisingly, the number of delegates attending our events has grown too. There were 906 attendees of the first CHI conference in 1982, while 3,804 (including telepresence robots) attended CHI 2016. Today more than 9,000 delegates participate in our 24 sponsored conferences. This growth raises challenges for volunteer workload, constrains venue choices, and puts pressures on budgets.

This growth has also led to a number of changes in how SIGCHI manages its conferences. Since 2006, SIGCHI has supported the creation of a steering committee for each of our sponsored conferences. Further, the current SIGCHI Executive Committee made some changes with the aim of more sustainable and resilient processes. In the past We have also recently formed a CHI conference steering committee that consists of 17 members with prior experience as CHI general chairs, technical program chairs, papers chairs, accessibility experts, and ACM operations. The steering committee members represent a diverse range of research topics and methods within our field. One important task the steering committee has taken on is to define a strategic plan for CHI conference locations, leading to a more predictable international rotation. Our five-year plan-which went into effect with CHI 2017-calls for two conferences in North America, one in Europe, one in Asia, and one at a wildcard location that will be selected to serve strategic goals to grow the field of HCI.

The CHI conference continues to evolve in response to community interests, new developments, and strategic initiatives. For example, recent CHI conferences have pioneered an increased emphasis on diversity and inclusion, offered courses to support members in communicating with the public, and created public outreach talks. The conferences have featured many community development events, supporting participation by members of our community from the Global South, offering career guidance and networking opportunities for early career HCI researchers and practitioners, and creating mentoring and cohort-building opportunities for underrepresented groups.

By the time you read this, our current terms as SIGCHI leaders will have come to an end. However, we are confident that the changes we We are confident that the changes we described here will help our family of conferences, including CHI, to better respond to the challenges and opportunities ahead. described here will help our family of conferences, including CHI, to better respond to the challenges and opportunities ahead for the field of human-computer interaction. We have tried to foster an open conversation between SIGCHI leadership and the entire SIGCHI community, and we encourage you to continue this with the new leadership. A good place to start is to follow SIGCHI on Twitter at @sigchi.


Raouf Boucekkine
email: raouf.boucekkine@univ-amu.fr

Thomas Seegmuller
email: thomas.seegmuller@univ-amu.fr

Alain Venditti
email: alain.venditti@univ-amu.fr

Carine Nourry

Advances in growth and macroeconomic dynamics: In memory of Carine Nourry

Keywords:

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

These results generalize and extend the main conclusions of [START_REF] Galor | A two-sector overlapping-generations model: a global characterization of the dynamical system[END_REF], [START_REF] Reichlin | Endogenous fluctuations in a two-sector overlapping generations economy[END_REF] and [START_REF] Nourry | Local indeterminacy under dynamic efficiency in a two-sector overlapping generations economy[END_REF] obtained under more restrictive conditions. Indeed, by providing detailed conditions expressed in terms of the sectoral elasticities of capital/labor substitution, [START_REF] Barinci | On equilibrium elasticities of substitution in simple overlapping generations economies with heterogeneous goods[END_REF] explicit the mechanisms generating business-cycles fluctuations. Building on a general description of technologies and preferences, this paper provides a significant progress in this highly demanding literature.

Since [START_REF] Uzawa | Optimum technical change in an aggregative model of economic growth[END_REF] and more recently [START_REF] Lucas | On the mechanics of economic development[END_REF], it is well recognized that human capital is a major driver of economic growth. Investments in human capital are individual and collective choices carrying significant external effects. In general, human capital externalities are considered through their impact on productivity. However, increasing studies in sociology show that human capital also affects welfare. In particular, [START_REF] Ross | The links between education and health[END_REF] find that better educated agents have a larger demand for health and are more in control of their life as they live in healthier conditions. They can then enjoy more consumption.

In line with this stream of research, [START_REF] Bosi | Externalities of human capital[END_REF] contribute to this special issue by exploring the implications of introducing different types of human capital externalities into the utility function, the production function and the human capital accumulation of a Lucas-type model without physical capital. 1 They study how these interact with the choice of time to work versus time to accumulate human capital, as well as their effects on growth and on the stability properties of equilibria. It is shown that growth can be no longer balanced and that the equilibrium can be globally indeterminate. This implies that two economies with identical preferences, technologies (of production and human capital accumulation) and initial endowment of human capital, may experience different growth paths. A taxation policy based on constant tax rate is then shown to speed up the accumulation of human capital.

While many papers study the effects of human capital on human capital accumulation (see for instance, de la Croix andDoepke, 2003, Tamura, 2001), very few papers focus on the impact of human capital as a positive externality on human capital accumulation. Among them, [START_REF] Mookherjee | Aspirations, segregation, and occupational choice[END_REF] study an overlapping generations economy where, depending on location, parents decide whether or not to educate their children, and [START_REF] Cavalcanti | Growth and human capital: a network approach[END_REF] focus on positive network externalities (local peer) on human capital accumulation in an overlapping generations model and reconsider the trade-off between growth and inequality. By computing the explicit trajectories and thus providing a global understanding of the dynamic properties, the paper of [START_REF] Bosi | Externalities of human capital[END_REF] constitutes a significant extension of this literature to the analysis of various human capital externalities on the accumulation of human capital and the associated impact on growth and macroeconomic instability.

The last financial crisis and more recently the Covid crisis have generated dramatic increases of debt levels in most countries raising the problem of debt financing. The control of the growth rate of public spending has then become a major concern for economists and policy-makers. Yet, the co-existence of various experiences across countries suggests that debt financing is a complex question. While most existing papers are concerned with closed economies (see for instance [START_REF] Chéron | Growth and public debt : what are the relevant tradeoffs?[END_REF][START_REF] Futagami | Debt policy rule, productive Ggovernment spending, and multiple Ggrowth paths[END_REF][START_REF] Nishimura | Fiscal policy, debt constraint and expectation-driven volatility[END_REF], it clearly appears now that borrowing on the international market can be more or less limited by collateral constraints, and that the share of public debt hold by residents may play a significant role.

1 Capital is not considered to simplify the analysis and to focus exclusively on the role of human capital.

In this special issue, [START_REF] Modesto | Growth and instability in a small open economy with debt[END_REF] provide with a theoretical exploration of the latter interconnected issues. To this end, they consider a small open economy with a credit constraint `a la [START_REF] Fahri | Bubbly liquidity[END_REF] and [START_REF] Hirano | Asset bubbles, endogenous growth, and financial frictions[END_REF], and a preference for domestic public bonds. In such a framework, there is non-substitutability between the different assets, productive capital, public debt and an international asset, and the economy is characterized by an investment multiplier. It is shown that whatever the level of the debt-output ratio, there always exists a high growth BGP which features expectationdriven fluctuations. Moreover, if the debt-output ratio is low enough, global indeterminacy arises as there is also a second BGP with a lower growth rate. But if the share of public debt held by domestic households is high enough, this second BGP is ruled out and global indeterminacy does not occur.

The key findings of this paper provide a significant improvement of the analysis of non substitutable assets in macrodynamic model. Indeed, most previous papers such as [START_REF] Morimoto | Debt policy rules in an open economy[END_REF], which also address the case of a small open economy, assume that the different assets, productive capital and domestic and external debt, are perfect substitutes. As a result, there is no portfolio choice for the households and only the level of total asset holdings plays a role. Such a framework does not allow to properly assess the impact of domestic holding of domestic debt on the stability properties of the economy. While essentially theoretical, by precisely focusing on the non substitutability of assets, the paper of [START_REF] Modesto | Growth and instability in a small open economy with debt[END_REF] is able to capture the case of the Japanese economy which is characterized by a very large debt, a large proportion of domestic public bonds owned by Japanese residents and a weak volatility of GDP.

Existence of equilibria

The second section is concerned with the existence of equilibria. Inefficiencies and multiplicities of equilibria explain the results of many papers of this special issue. They were also at the core of the scientific works of Carine Nourry. Two key ingredients to generate them are of course the presence of market failures and the introduction of sufficiently general models. The existence of equilibria in these contexts is still an open question, especially in multi-period models, which imply intertemporal arbitrages. Both market inefficiencies and generalization of preferences break from some important difficulties and ask for new answers. The two papers in this section are concerned with these issues, the first one dealing with the existence of equilibria with collateral constraints and endogenous production, and the second one in an infinite horizon framework where preferences do not satisfy some too standard properties. Despite the fact that the existence of equilibria is a fundamental issue for economists, these two papers also answer to other questions, that is, the interplay between the real and financial spheres of economies and the selection of equilibria.

The empirical evidence on the pattern of bankruptcy illustrates the interplay between finance and real economic activity. A central question is therefore the financing of firms' investments when financial markets are incomplete. The first contribution by [START_REF] León-Ledesma | Production, bankruptcy, and financial policies under collateral constraints[END_REF] studies an extension of the incomplete markets' general equilibrium model in which firms can default and therefore bankruptcy is possible. The production aspects of the model with default and collateral in a novelty of the paper. Their setting is characterized by endogenous production, and collateral constraints involve all the commodities available for consumption and production in the economy. Because the owners of firms have unlimited liability, lenders can seize the value of collateral and future production. This introduces endogenous default. Because of this endogeneity, lenders have a portfolio of assets issued by producers but cannot anticipate the identity of the firm defaulting. Thus, lenders anticipate a default rate that depends on the average level of production and is therefore counter cyclical. Finally, in order to avoid an equilibrium with no production, an insurance mechanism is introduced.

In this framework, the two key theorems in corporate finance, namely the Fisher's separation theorem and the Modigliani-Miller theorem, are generally not satisfied. Thus, in general, the separation between the financial decisions of firms and their owners is not possible, which implies that the real and financial spheres of the economy are not disconnected. This is important for the design of financial policies. Finally, under usual assumptions on utilities and technologies, the existence of equilibria is shown, and the paper discusses the nature of the inefficiencies due to the occurrence of bankruptcy. Because of an insurance premium, the equilibrium is constrained efficient.

Recursive utility describes classes of intertemporal utility functions that are tractable and extensively used in macro-dynamic models. Optimal growth models in discrete time are clearly the main application of recursive utility functions. When the model considered is sufficiently general, a relevant question is to find a class of utility functions that solves the Koopmans equation for a given aggregator. Some solutions to this problem have been found when the aggregator satisfies some Lipschitz condition. When this is not the case, [START_REF] Marinacci | Unique solutions for stochastic recursive utilities[END_REF] proposed aggregators that did not fit into the previous literature. The name of these aggregators are the Thompson aggregators. They proposed new methods to solve the Koopmans equation for such a given operator. The existence of extremal solutions is however a non-constructive result.

In their contribution to this special issue, Becker and Rincón-Zapatero (2021) go a fundamental step ahead: they develop a computationally motivated methodology which offers a selection principle for numerical solutions of recursive macrodynamic models where theory suggests that there are multiple fixed points. They obtain a constructive result. They show that extremal fixed points exist using successive approximations as soon as the conditions of the Tarski-Kantorovich fixed point theorem are met. The proof is based on the verification of an order continuity property. Their result provides qualitative features of the extremal solutions, as semi-continuity and concavity.

Migration and networks

The growth enhancing effect of migrations in both host and sending countries has been a quite active research area in growth and dynamic macroeconomics since the 70 s. A fundamental nexus between human migrations and economic growth is human capital accumulation, in particular via the inherent brain drain (see the early contribution of [START_REF] Rodriguez | Brain drain and economic growth: A dynamic model[END_REF]. Whether the latter has a net devastating effect on the development of the sending countries, as initially thought, is still an intensively debated issue: induced education in the host country (or the socalled brain gain mechanism as first suggested by [START_REF] Mountford | Can a brain drain be good for growth in the source economy?[END_REF] and remittances by skilled migrants (see [START_REF] Faini | Remittances and the brain drain: Do more skilled migrants remit more?[END_REF] have been among the most frequently suggested channels through which the direct (negative) effect due to the brain drain may end up dominated.

In their contribution to this special issue, [START_REF] Destrée | Migration, remittances and accumulation of human capital with endogenous debt constraints[END_REF] propose an important theoretical extension incorporating, in addition to the two latter mechanisms, endogenous debt constraints in the sending countries. More precisely, they consider an endogenous growth model based on human capital accumulation where agents face an endogenous debt constraint to finance their education in the home country while they receive remittances from their emigrated children. The debt constraint ingredient is a key feature of developing economies, and as explained in the seminal work of Banaerjee and Newman (1993), it plays a crucial role in the accumulation of human capital in these economies. [START_REF] Destrée | Migration, remittances and accumulation of human capital with endogenous debt constraints[END_REF] assume a non-commitment setting à la de la [START_REF] De La Croix | Education and growth with endogenous debt constraints[END_REF] where individuals may choose to default on their debt and be excluded from the asset market. They show that remittances tend to tighten the borrowing constraints for a given level of interest rate, but may enhance growth at the equilibrium. Based on the existence of multiple equilibria, the model is able to replicate both negative and positive impacts of migration and remittances on economic growth. A calibration of the model based on 30 recipient economies shows however that the global effect of migration and remittances on education and growth is positive for a majority of them.

Another increasingly important research question is the role of social networks, not only in driving migrations, but also in connection with labor mobility (see for example [START_REF] Calvó-Armengol | Job contact networks[END_REF], educational mobility (see a recent study by [START_REF] Stephany | It deepens like a coastal shelf: Educational mobility and social capital in Germany[END_REF] and the pace of human capital accumulation, and thus in fine with the development process. The concept of social network is indeed central in many disciplines: it is deeply rooted in sociological research, in anthropology, geography and political science, and about to become equally central in several streams of the economic literature. In this special issue, we provide with two contributions focusing on the role of social networks. The first one by Domingues Dos Santos and Taugourdeau (2021) studies the role of social networks in international migrations. This article is essentially theoretical but it has been carefully designed to capture some of the salient characteristics of the Portuguese migration to France. To the best of our knowledge, this is one of the few social networks-related papers at the intersection of the migrations and labor market streams. The second by Augeraud-Véron et al. ( 2021) studies the implications of welfare-enhancing social interactions in the creation of cities and their size via the rigorous concept of urban equilibria. This paper makes progress on one of the most difficult technical problems involved by local interactions, which reveals far trickier to study than the global interactions case in urban economics (see an early treatment of this case in [START_REF] Mossay | On spatial equilibria in a social interaction model[END_REF].

The crucial role of social networks has been highlighted to explain behaviors in the labor market and migratory patterns. However, these two concerns are usually disconnected. The interplay between immigrants' informational network, job search activities, migration and concentration in some specific industry has not yet been analytically addressed. The model of Domingues Dos Santos and Taugourdeau (2021) fills this gap. Social networks are taken into account in a matching model to illustrate the persistent situation of Portuguese immigrants in the French labor market. Indeed, they are still concentrated on a sector with low productivity, namely the construction sector.

The paper develops an original matching model that highlights that the employment concentration of the Portuguese community can mainly be explained by their social network. There are two sectors with endogenous allocation of the labor force between sectors and social networks that favor the transmission of job information. Social networks can induce sector concentration even when productivities and entry costs are perfectly symmetric, but they can also trap workers in poorly productive sectors. The transmission of job information within a community improves the matching efficiency, which reduces unemployment and promotes sector concentration. Hence, the model explains the two main specificities of the Portuguese labor force in the French labor market: a low unemployment rate and a high sector concentration. It also highlights the intergenerational persistence of both these features.

As argued above, the urban economics literature typically assumes that interactions are global: all the residents are willing to interact with every other [START_REF] Mossay | On spatial equilibria in a social interaction model[END_REF] and, all firms make economic transactions with every other [START_REF] Mossay | Urban structures with forward and backward linkages[END_REF]. Augeraud-Véron et al.'s contribution to this special issue is the first theoretical attempt to cope with local interactions. Due to travel costs, economic agents may not find it optimal to interact with every other, and interactions remain local. In their spatial model, Augeraud-Véron et al. ( 2021) study how a given mass of identical individuals would locate in a given space assuming that utility in any location depends on consumption of both a composite good and land space, plus the so-called social surplus (that is the gains from local interactions at that location). Landlords rent land (both for residential and farming purposes). An urban equilibrium is reached when individuals have no more incentives to move. The challenge is to characterize and compute the equilibrium population density.

The key finding of the study is that the equilibrium population density function is a solution to a second order advanced-delay differential equation. In other words, changes in population density at any urban location depend on the density at some specific distance (capturing the interaction ''window'' of individuals) to the left and right hand of this location. The differential equation uncovered is functional, and it is extremely hard to solve. In an intertemporal frame, it corresponds to a differential equation with both time lags and time leads. These equation would arise in optimal growth models with vintage capital as in [START_REF] Boucekkine | Vintage capital and the dynamics of the AK model[END_REF] but the spatial model developed by [START_REF] Augeraud-Véron | Local social interaction and urban equilibria[END_REF] has additional features which make it far more intricate. Besides confirming that the usual properties of urban equilibria also hold under local interaction (albeit with some qualifications), the authors bring out several novel predictions about the role of local versus global interactions in the formation of (monocentric/polycentric) cities. Even more, the authors close their article with an application of their local interaction framework to population dynamics under an epidemic threat as the ongoing Covid-19 epidemic.

Inequalities and income distribution

The last section of this special issue is specifically devoted to the analysis of inequalities, and includes four original contributions. Three take a positive approach: Benhabib and Hager (2021) present a theory of ''revenue diversion'' by managers and its implications for income distributions, [START_REF] Constant | Pollution, children's health and the evolution of human capital inequality[END_REF] study the persistence of human capital inequalities due to pollution, while [START_REF] Boucekkine | A theory of elite-biased democracies[END_REF] build up a theory of elite-biased democracies where in contrast to ''pure'' democracies, the incumbent autocrat allied with an insider minority remains in power without enforcing the redistribution rate preferred by the majority. The fourth contribution due to de la Croix and Doepke ( 2021) is normative: the authors propose a new approach to the so-called optimal population size problem (see for example [START_REF] Blackorby | Intertemporal population ethics: Critical-level utilitarian principles[END_REF] with several contextual implications.

Benhabib and Hager's highly insightful contribution to this special issue brings the casual readers to the origins of the debate on the shape of income/earning distributions (in particular to the relatively unknown pioneering work of [START_REF] Fréchet | Sur les formules de répartition des revenus[END_REF] and then displays a simple and appealing theory of income distributions with ''revenue diversion'', which they further: (i) connect to the historical debate just above mentioned, and (ii) illustrate with some rough quantitative exercises.

A key aspect of the theory is the allocation of talents across occupations, where ''talent'' has to be understood in a broad sense (say a combination of technical and social skills). If the distribution of talents were fully observable, then one could infer the earnings distribution for a given mapping of talents into earnings. But the authors note that talents are not fully observable: there is room for ''revenue diversion'', that is revenue gains not closely remunerating talents but diverted by a certain class of personal, called ''managers'' (as opposed to ''workers'') in the theory produced by [START_REF] Benhabib | Revenue diversion, the allocation of talent, and income distribution[END_REF]. This echoes previous work by [START_REF] Murphy | The Allocation of talent: The implications for growth[END_REF] where ''engineers'' are opposed to ''lawyers''. This is also pretty much in line with an ongoing debate on the gigantic business incomes of the managers of the superstar companies of the digital economy (see the recent work by [START_REF] Jones | A schumpeterian model of top income inequality[END_REF], on top income inequality in the US). Benhabib and Hager's allocation of talent theory allows to get that, with or without revenue diversion, the overall distribution of income is hump shaped, and is given by a Pareto distribution above the median (as stated by [START_REF] Fréchet | Sur les formules de répartition des revenus[END_REF]. Some illustrative quantitative exercises are additionally provided.

Inequalities can be addressed in terms of the effects of pollution. Pollution is a significant reason for health problems (see for instance Raffin andSeegmuller, 2014, 2017;[START_REF] Palivos | Pollution abatement as a source of stabilization and long-run growth[END_REF]. Children are identified as special victims to these health effects of pollution. The consequences are not only in the short term, but also in the long term. By increasing absenteeism or affecting learning skills, the health effects of pollution have consequences on human capital and income when individuals become adults. The health effects of pollution are thus characterized by inequalities inside each generation. Indeed, children with lower socio-economic status are more vulnerable and exposed to the health consequences of pollution.

Despite their importance, the consequences of inequalities due to pollution have been studied only in a few theoretical papers. [START_REF] Constant | Pollution, children's health and the evolution of human capital inequality[END_REF] provide an analysis which contributes to make up for this lack. They develop an overlapping generations model where individuals have heterogeneous human capital. Children suffer from air pollution, but their parents can mitigate this effect by investing in health. These different aspects contribute to the accumulation of human capital. The pollution rate of production and the initial level of inequalities determine the long run behavior of the economy. In particular, if the production is highly polluting, inequalities will persist over time and the economy can even be relegated into an inequality trap. Indeed, pollution affects more poorer children who will accumulate less and less human capital. [START_REF] Constant | Pollution, children's health and the evolution of human capital inequality[END_REF] also study environmental and health policies which are able to reduce inequalities. Environmental maintenance financed by polluters can be a good tool when the initial inequality and the pollution emission are not too high. Otherwise, adding a health policy, which consists of health subsidies, could be a relevant option. [START_REF] Boucekkine | A theory of elite-biased democracies[END_REF] tackle another type of ''revenue diversion'' within autocratic regimes with insider minorities. They rely on the important work of the political scientists, [START_REF] Albertus | Authoritarianism and the Elite Origins of Democracy[END_REF], who noted that a significant fraction of democracies are substantially departing from what is usually associated with the very concept of democracy, e.g. inclusiveness, income redistribution from the rich to the poor, strong welfare states. [START_REF] Boucekkine | A theory of elite-biased democracies[END_REF] provide with further empirical evidence of these ''impure'' democracies: in particular they show that about 40% of formal democracies which have emerged at some point since 1960 still operated under autocratic constitutions in 2006. Typically, these democracies are elite-biased: they are less egalitarian than popular democracies both in terms of income distribution and access to political power.

The main contribution of this paper is theoretical however: the authors extend the basic political transition game-theoretic model of [START_REF] Acemoglu | Economic Origins of Dictatorship and Democracy[END_REF] to identify conditions under which elite-biased democracies would arise as an economic-political equilibrium. In particular, the population is split into 2 groups, a minority and a majority, with the additional crucial ingredient that minority enjoys a preferential treatment or benefit from fiscal particularism under autocracy (insider elite in the terminology of [START_REF] Albertus | Authoritarianism and the Elite Origins of Democracy[END_REF]. As a result, the preferred tax rate of the majority member is likely to be significantly higher than in a situation, as in the Acemoglu and Robinson's benchmark (see also [START_REF] Boucekkine | On the timing of political regime changes in resource-dependent economies[END_REF], where there is only one source of income discrimination. Elite-biased democracies may then arise if one source of discrimination, fiscal particularism, is officially removed, and replaced by a more goodlooking coalition, even though the involved redistribution to the majority members is lower than the counterpart under pure democracy.

The optimal population size problem is an old normative problem, which has been the subject of numerous contributions and approaches since the late 60 s (and even much before, see the survey part in [START_REF] Dasgupta | On the concept of optimal population[END_REF]. It is however still open, and de la Croix and Doepke (2021) are providing with a novel and intriguing approach in this special issue.

A key issue arising in the standard welfarist approaches is that they ultimately require evaluating the welfare of nonexistent people, because some people exist only in some allocations but not in others. This is a major problem which is has been heavily discussed in economics (see for example, [START_REF] Golosov | Efficiency with endogenous population growth[END_REF] and ethics (see [START_REF] Parfit | Reasons and Persons[END_REF] and his repugnant conclusions). To deal with this essential problem, de la Croix and Doepke (2021) advocate for a soul's view approach with introspection as the accompanying method for comparison of populations (of different sizes)

For the authors, the key of the problem is to find an interpretation ''where being alive and being unborn are not mutually exclusive, but merely different states which are experienced by one and the same being over time''. And this can be even made operational: it is enough to assume that the world is endowed with a fixed supply of souls who get reincarnated from time to time in different human bodies. de la Croix and Doepke (2021) elaborate on this conceptual approach to derive a rich theoretical analysis (including comparison with leading alternatives) and discuss some applications to concrete problems involving long-term environmental risks.

✩ This work was supported by French National Research Agency Grants ANR- 08-BLAN-0245-01 and ANR-17-EURE-0020, and by the Excellence Initiative of Aix-Marseille University -A*MIDEX. * Corresponding author at: AMSE -5