Simon Cornée
email: simon.cornee@univ-rennes1.fr

Damien Rousselière
email: damien.rousseliere@agrocampus-ouest.fr

Governing Common-Property Assets: Theory and Evidence from Agriculture*

Keywords:

This paper introduces a refined approach to conceptualising the commons in order to shed new light on cooperative practices. Specifically, it proposes the novel concept of Common-Property Assets (CPAs). CPAs are exclusively human-made resources owned under common-property ownership regimes. Our CPA model combines quantity (the flow of resource units available to members) and quality (the impact produced on the community by the members' appropriation of the resource flow). While these two dimensions are largely pre-existing in the conventional case of natural common-pool resources, they directly depend on members' collective action in CPAs. We apply this theoretical framework to farm machinery sharing agreements-a widespread grassroots cooperative phenomenon in agriculture-using a systematic literature review to generalise the findings from a sample of 54 studies published from 1950 to 2018. Our findings show that in successful CPAs, members endorse and do not deviate from a quantityquality equilibrium that is collectively agreed upon. Despite the existence of thresholds for both quantity and quality due to (axiological) membership heterogeneity, qualitative changes in respect of the common good are possible in CPAs that promote democratic practices. Our study has potentially strong implications for developing ethics in cooperatives and the sustainable development of communities worldwide.

Introduction

Cooperatives have a long history as key players in the socioeconomic development of communities worldwide [START_REF] Stiglitz | Moving beyond market fundamentalism to a more balanced economy[END_REF]. As democratic organisations managed by their members, cooperatives are distinguished from investor-owned corporations by their orientation towards broader social goals. However, despite their economic significance in agriculture, banking, insurance, and healthcare, cooperatives have been largely ignored in the recent literature [START_REF] Kalmi | The disappearance of cooperatives from economics textbooks[END_REF]. The commons paradigm offers a promising opportunity to reconceptualise cooperative practices and more specifically their governance. The theories of the commons challenge the primacy of the private property paradigm and address the necessity of investigating alternative ways of conducting economic activities and their ethical consequences [START_REF] Peredo | Decommodification in action: Common property as countermovement[END_REF][START_REF] Périlleux | Understanding cooperative finance as a new common[END_REF].

While there is evidence of commons experiences from time immemorial [START_REF] Dardot | Commun. Essai sur la révolution au XXe siècle[END_REF][START_REF] Polanyi | The great transformation: Economic and political origins of our time[END_REF], the recent surge of academic interest in the commons, especially in the fields of business and economics, owes a great deal to Ostrom's influential work. In particular, she refutes [START_REF] Hardin | The tragedy of the commons[END_REF] contention that natural common-pool resources (CPRs) (e.g. water, grassland, fishing resources) are doomed to exhaustion by identifying the key institutional arrangements that allow for their sustainable management [START_REF] Ostrom | Governing the commons: The evolution of institutions for collective action[END_REF]). The scope of the CPR framework has since been considerably broadened to re-conceptualise shared resources and now embraces a variety of 'new commons' encompassing all types of fields, any combination of property rights, and natural as well as human-made resources [START_REF] Hess | Mapping the new commons[END_REF]). This framework is quite accommodating, given the commons continuum has too many distinctive features for it to be captured in a universal set of principles [START_REF] Bollier | The growth of the commons paradigm[END_REF]. In this paper, we argue that a more bounded conceptualisation of the commons is needed to shed new light on the cooperative realm. We therefore propose the novel category of common-property assets A c c e p t e d m a n u s c r i p t (CPAs), which delimits the commons approach in two respects. First, CPAs are exclusively commons that are created by people through collective action, in other words, they are humanmade resources. Second, to account for the legal status of cooperatives, we postulate that CPAs have an exclusive property regime (common property).

A major contribution of our approach is that by adapting CPR theory to CPAs, we are able to understand the governance of cooperatives from the perspective of generating-as opposed to conserving-a specific flow of resource units. In the wake of Ostrom's work, the existing institutionalist framework on the management of CPRs has mainly focused on establishing a set of institutional arrangements (i.e. rules and norms) that lead to sustainable withdrawal rates to ensure the renewal of a pre-existing (natural) resource stock. In CPAs, the resource stock does not pre-exist but varies as a function of the cooperation level among members.

Consequently, CPA members can increase the quantity (i.e. the flow of resource units available to them) not only by modifying the institutional arrangements regulating the withdrawal rate (as in CPRs) but also by expanding the size of the resource stock (unlike in CPRs). Moreover, focusing only on the quantity of a commons leaves open the question of whether and, subsequently, to what extent the members' appropriation of the resource flow produces a positive impact on themselves and their community. This quality dimension is especially crucial in CPAs (with respect to CPRs) because it is determined both by the way commoners use and appropriate the resource flow (as in CPRs) and by the substance or nature of the resource stock (unlike in CPRs), which has to be collectively agreed by CPA members.

The combining of quantity and quality in our CPA model expands the institutionalist perspective of commons governance by also taking into consideration the ethics perspective.

Regarding quantity, the members' propensity to cooperate does not rely solely on institutional arrangements but is also firmly rooted in an ethical fabric. More importantly, the quality A c c e p t e d m a n u s c r i p t dimension clearly addresses the moral question of how the human action of creating and maintaining a CPA helps members and their community to secure a better life [START_REF] Greenwood | Focusing on ethics and broadening our intellectual base[END_REF]. This refers in particular to the ethics of the common good, which is concerned with how much practices organised through collective action contribute to human flourishing [START_REF] Meyer | Money and the commons: An investigation of complementary currencies and their ethical implications[END_REF]. In the cooperative context, our two-dimensional CPA model addresses essential ethical issues, such as the phenomenon of organisational degeneration, and echoes the recent questioning-with regard to the long history of cooperatives-of the impacts of their actions on communities [START_REF] Chomel | Déclaration de l'ACI: la continuité au risque de l'irréalité[END_REF]. 1 The agricultural sector offers fertile ground for testing our CPA theoretical approach. Despite its multifaceted challenges, including low economic returns, negative environmental externalities, and pressure from urban sprawl [START_REF] Wu | Urbanization and the viability of local agricultural economies[END_REF], the sector is characterised by a dynamic cooperative fabric at grassroots level, which generates innovative socioeconomic and ecological practices in both developed and developing countries [START_REF] Merrett | Cooperatives and local development: Theory and applications for the 21st century[END_REF]).

This study focuses on a widespread form of these community-based cooperative practices, namely farm machinery sharing arrangements. These arrangements are established by selforganised groups of farmers willing to collectively invest in and manage machinery and other equipment. The presence and institutional nature of these arrangements vary considerably according to national contexts. In France, where these arrangements are most prevalent, approximately half of all farms are members of one of the 12,600 active CUMAs (Coopératives d'Utilisation de Matériel Agricole). Access to affordable, technologically up-to-date machinery is deemed critical to a farm's survival, whatever the national context, because mechanisation costs are one of their largest expenditures. 2 To explore these burgeoning and innovative yet under-researched farm machinery cooperative agreements, we conduct a systematic literature review (SLR) of 54 documents published A c c e p t e d m a n u s c r i p t between 1950 and 2018. This methodology is particularly appropriate for investigating the specificities of commons because it allows the findings from multiple case studies to be generalised. Unlike traditional narrative reviews, SLRs ensure a replicable and transparent research process (e.g. [START_REF] Hansen | The sustainability balanced scorecard: A systematic review of architectures[END_REF][START_REF] Mcleod | Organizational ethics research: A systematic review of methods and analytical techniques[END_REF][START_REF] Parris | A systematic literature review of servant leadership theory in organizational contexts[END_REF].

Our findings indicate that members of successful CPAs manage to reach a consensual agreement on quantity and quality dimensions and do not prioritise the former over the latter.

Qualitative changes aimed at the common good depend on democratic, participatory debates enabling members to harmonise their values in the CPA decision arena. However, we observe that CPA expansion possibilities-albeit theoretically unbounded-are hindered by (axiological) heterogeneity among members.

The remainder of this paper is organised as follows. Section 2 presents the CPA theoretical framework. Section 3 describes the methodology and introduces the data. Section 4 identifies the benefits and costs for CPA members and examines the critical factors that ensure CPA success. Section 5 discusses the findings, and Section 6 concludes.

Theoretical Framework

The Concept of Common-Property Assets

CPAs (like CPRs) are characterised by a shared, renewable resource stock that generates a flow of resource units for appropriation or use by individual members [START_REF] Ostrom | Governing the commons: The evolution of institutions for collective action[END_REF]). The economic nature of the commons is defined by the criteria of subtractability and excludability [START_REF] Hess | Ideas, artifacts, and facilities: Information as a common-pool resource[END_REF][START_REF] Ostrom | Rules, games and common-pool resources[END_REF]). While high subtractability (i.e. rivalry in the consumption) implies the "congestion, overuse, pollution or destruction [of the shared resource] unless limits are devised and enforced" (Hess and Ostrom 2003, p. 13), it is difficult to prevent a user from A c c e p t e d m a n u s c r i p t subtracting units at a moderate cost (excludability). Herein lies the social dilemma of commons management.

To solve this social dilemma, CPRs and CPAs both rely on forms of reciprocity-based institutional arrangements that are neither market-nor state-mediated. CPAs are distinguished from CPRs in two respects. First, while CPRs primarily involve natural resource systems, CPAs are restricted to human-made commons. Second, their ownership structures differ. CPRs can be owned under any property regime, including governmental authorities, community groups, corporations, and private individuals [START_REF] Hess | Ideas, artifacts, and facilities: Information as a common-pool resource[END_REF], while CPAs are exclusively defined by formal or informal common-property ownership regimes to capture cooperative practices. More specifically, of the five property rights (i.e. access, withdrawal, management, exclusion, and alienation) defined by [START_REF] Schlager | Property rights regimes and natural resources: A conceptual analysis[END_REF] as being potentially applicable for CPRs, CPA members share the legal rights only to access, harvest and manage the resource and to legally exclude non-members. The alienation right is considerably limited in CPAs because members cannot sell on their access, use, exclusion, or management rights without the other group members' approval.

Importantly, these two distinctive dimensions interact with one another. CPRs can accommodate flexible bundles of property rights because they rely on pre-existing natural resources. In contrast, because CPAs are created ex nihilo and do not rely on a pre-established substance, their very existence depends solely upon their restrictive ownership structure. In general, CPA members enjoy the usufruct of the assets, but they cannot appropriate them. For example, cooperatives can use the asset-lock principle, whereby a large fraction of the profits is kept in indivisible reserves to be reinvested in assets [START_REF] Périlleux | Understanding cooperative finance as a new common[END_REF]. The two specific CPA attributes we have just expounded introduce major changes in our way of conceiving the sustainable management of commons. We will now examine these changes from a quantity and quality perspective. The quantity perspective largely elaborates on the institutionalist literature that has sought in recent decades to determine the conditions under which collective action and self-governance, especially through the design of a variety of institutional arrangements, could lead to the conservation of natural resources [START_REF] Baland | Halting degradation of natural resources: Is there a role for rural communities?[END_REF][START_REF] Ostrom | Governing the commons: The evolution of institutions for collective action[END_REF][START_REF] Ostrom | Understanding institutional diversity[END_REF][START_REF] Ostrom | Covenants with and without a sword: Selfgovernance is possible[END_REF][START_REF] Wade | Village republics: Economic conditions for collective action in South India[END_REF]. Quantity is defined by the flow of resource units available to users and is affected by two factors: (i) the resource stock and (ii) the institutional arrangements governing the withdrawal policy. In the conventional case of natural CPRs, the resource stock pre-exists collective action and is finite because its increase is limited by biophysical conditions. Accordingly, collective action only focuses on designing institutional arrangements that ensure that the withdrawal rate does not exceed the renewal rate to preserve the CPR quantity. In contrast, CPA users have to agree not only on a practicable withdrawal rate but also on the size of the resource stock (e.g. total production assets), which is adjustable and potentially infinite and dependent entirely and endogenously on collective action.

Quantity and Quality in Commons

While the quantity perspective inherently implies a degree of ethical consideration (e.g. fairness of rules), it disregards some key ethical issues, which can be approximated by the concept of the common good. In business ethics, this is defined as "the creation of communities, the values and ties binding social actors, and the positive impacts human activities can have on society" (Meyer and Hudon 2019, p. 279). This concept was nurtured in the Aristotelian ethos of virtue [START_REF] Sison | Guest editors' introduction reviving tradition: Virtue and the common good in business and management[END_REF]) and in the social doctrine of the Catholic Church [START_REF] Argandoña | The stakeholder theory and the common good[END_REF][START_REF] Melé | Integrating personalism into virtue-based business ethics: The personalist and the common good principles[END_REF][START_REF] Melé | The firm as a "community of persons": A pillar of humanistic business ethos[END_REF]. It may also relate to John Dewey's pragmatism [START_REF] Fesmire | John Dewey and moral imagination: Pragmatism in ethics[END_REF]. In pursuing the common good, humans as social beings develop themselves as persons-or enhance their "individuality" (Dewey 1986, p. 244)-in their relations with others and concurrently A c c e p t e d m a n u s c r i p t contribute to a collective flourishing. Taking serious account of the idea of the common good considerably enhances our thinking on the sustainable management of commons and reveals a number of important ethical issues, which we propose categorising as quality.

We define quality as the positive impact of the users' appropriation of the resource flow on themselves (at individual and collective levels) and their community. Quality derives from a combination of two factors: (i) the substance of the resource stock and (ii) the way in which the commoners appropriate and use the resource flow. In natural CPRs, users can only rely on the latter factor to improve their livelihood because the substance of the resource stock is predetermined. For example, the appropriators of a water basin may institutionalise communitybased practices aimed at preventing contamination and promoting a socially efficient use. In contrast, the members of a CPA define quality by deciding on both the nature of the resource stock and the use of the resource flow. Through collective action, the members determine the type of shared assets (e.g. high-end, environmentally friendly production assets) and the way they use them. For instance, a similar asset may have either a positive or negative impact on the environment according to members' practices and the context in which it is used.

The quality perspective is an under-researched area in the literature on (natural) CPRs. The few studies dealing with this issue have generally considered the goal of improving community livelihood in opposition to the quantitative aspects of natural resource conservation. This opposition is rationalised by misalignments in time horizons. While conservation implies a long-term perspective, users may seek to increase community wellbeing by reaping short-term benefits thereby risking resource depletion [START_REF] Baland | Halting degradation of natural resources: Is there a role for rural communities?[END_REF]. However, more recent evidence indicates that these misalignments are not insurmountable provided that the wider community, rather than just the members, is actively involved in the rule-making process [START_REF] Persha | Social and ecological synergy: Local rulemaking, forest livelihoods, and biodiversity conservation[END_REF].

A c c e p t e d m a n u s c r i p t

The Conditions of Existence and Expansion for CPAs

In all CPAs, there is an (explicit or implicit) agreement on the quantity and quality of the units extractable from the resource stock. Each quantity-quality equilibrium materialises in a series of benefits and costs for members at individual level according to their respective discount rates, information-processing abilities, social preferences, community focus, and ethical values. An enriched cost-benefit analysis, which includes rational as well as axiological and sociological elements in decision-making, does not presuppose utilitarian moral theory and coincides with the business ethics perspective on the common good. A cost-benefit analysis typically differentiates direct (tangible) from indirect (intangible) elements in decision-making.

Compared to direct benefits and costs, indirect benefits and costs are more difficult to identify and quantify at individual level, and they only appear once the CPA is already established [START_REF] Schmidtz | A place for cost-benefit analysis[END_REF]. Accordingly, direct benefits correspond to economic benefits (e.g. profit increase). Direct costs include the non-strategic, fixed costs inherent to coordination that would exist regardless, even in a hypothetical world where all agents were acting with good will.

Indirect benefits, such as experience transfer among CPA members, come about via a mediating effect. Indirect costs are linked to the potentiality of strategic behaviour (i.e. opportunism) from at least some members, including free-riding, monitoring, and enforcement. The aggregation of these benefits and costs at collective level allows us to derive two propositions that characterise the emergence and development of CPAs.

Condition of existence.

Members must share a minimal willingness to cooperate in order to launch a CPA. If the level of cooperation is insufficient, no CPA institution will emerge because an insufficient number of members, in their respective individual choice arenas, believe that the direct potential benefits from cooperation surpass the direct costs. Thus, a CPA does not exist until a minimum collective level of cooperation (say X) is reached (Proposition 𝑃 1 ).

A c c e p t e d m a n u s c r i p t

Condition of expansion. Once the threshold X is reached, the CPA is established, and the members can begin appropriating the resource flow. In so doing, the CPA members experience unexpected indirect benefits and costs resulting from the collective action. Thus, a CPA is sustainable only if, for a given quantity and quality, the direct and indirect benefits from collective action exceed the direct and indirect costs (Proposition 𝑃 2 ).

How can we identify the conditions for which propositions 𝑃 1 and 𝑃 2 are achievable? [START_REF] Ostrom | Governing the commons: The evolution of institutions for collective action[END_REF] leading work synthesises the factors underpinning the successful management of natural CPRs in eight key design principles for sustainable CPR institutions. In their review of the profusion of empirical studies evaluating [START_REF] Ostrom | Governing the commons: The evolution of institutions for collective action[END_REF] While this analytical framework is useful in terms of understanding the sustainable management of natural CPRs, it is of more limited relevance in the case of CPAs. It succeeds in capturing the cooperative patterns that occur when a CPA is launched (i.e. when the quantitative and qualitative dimensions have already been agreed upon and stabilised by the commoners) but fails to entirely account for the emergence and evolution of a CPA (i.e. how the minimal cooperation threshold X is reached and then exceeded). This updated framework should be therefore supplemented by the CPA group characteristics that initiate and foster within-group cooperation. As suggested by [START_REF] Cox | A review of design principles for community-based natural resource management[END_REF], we draw on [START_REF] Agrawal | Common property institutions and sustainable governance of resources[END_REF] A c c e p t e d m a n u s c r i p t framework and retain five attributes from his study: (G1) small size; (G2) successful past experience of collective action by group members; (G3) appropriate leadership; (G4) interdependence among group members; and (G5) group members' shared norms and homogeneity of identities and interests. 4 Together, [START_REF] Ostrom | Governing the commons: The evolution of institutions for collective action[END_REF] framework as updated by [START_REF] Cox | A review of design principles for community-based natural resource management[END_REF] and [START_REF] Agrawal | Common property institutions and sustainable governance of resources[END_REF] framework provide a robust analytical grid for studying, from an institutionalist perspective, the establishment of institutional arrangements governing CPA organisations-especially in relation to CPA quantity. However, as argued by Meyer and Hudon (2019, p. 288) in their "ethos of social commons", this institutionalist perspective has little to say on the contribution of CPAs to the common good. It should therefore be supplemented by an ethics approach to examine the processes through which the values and preferences embodied in individuals aggregate and transform themselves into collective preferences and choices and to consider the consequences of this transformation on the CPA members and their community. At least two issues could be addressed in an analysis of these processes. First, the institutionalisation process underlying collective action in CPAs raises the question of the place that should be given to rules relative to or in interaction with other (more informal) institutional phenomena, such as shared values and generated moral norms [START_REF] Jones | The experience and evolution of trust: Implications for cooperation and teamwork[END_REF]. Second, reliance on the concept of the common good requires an examination of the institutional arrangements that enable CPA members to concomitantly foster their individuality and contribute to their community wellbeing [START_REF] Peredo | Toward a theory of community-based enterprise[END_REF].

Research Field and Methodology

Overview of Farm Machinery Sharing Cooperative Arrangements

The agricultural sector is characterised by a dense and vibrant fabric of self-organised, community-level initiatives. Farm machinery sharing arrangements typify these initiatives.

A c c e p t e d m a n u s c r i p t

Although unevenly represented globally, these arrangements are widespread in the major Western countries. Table 1 shows all the countries identified in the literature as having farm machinery sharing agreements and provides estimates of the coverage and most common legal institutional arrangements.

***Insert Table 1 about here*** Among the diversity of farm machinery sharing practices found in the data, the following four institutional forms predominate: mutual aid, machinery partnerships, machinery rings, and machinery cooperatives. 5 Table 2 presents these four categories (plus that of individual ownership) according to the bundles of property rights available to the respective members. It indicates that only machinery partnerships and machinery cooperatives meet the requirements for classification as CPAs. The common property nature of these two categories gives farmers the rights of access, withdrawal, management, and exclusion, but not alienation. Machinery partnerships are established on a voluntary basis between farmers who need the same type of equipment, with members defining the purchasing and operating policies. This category covers a wide variety of arrangements in terms of degree of formality, ranging from handshake agreements to limited liability corporations [START_REF] Artz | A return of the threshing ring? A case study of machinery and labor-sharing in Midwestern farms[END_REF]. This is not a recent phenomenon.

For example, approximately one-quarter of McCormick's reapers were jointly bought by two or more individuals in the 1850s in the United States [START_REF] Olmstead | Beyond the threshold: An analysis of the characteristics and behavior of early reaper adopters[END_REF]. Machinery cooperatives are very similar in practice to partnerships but have a stronger common property regime because they operate under the cooperative law. They do not own any machinery, nor do they undertake any farm work.

***Insert

In sum, partnerships and cooperatives are representative cases of CPAs in agriculture.

Machinery assets are their typical common-property resource stock, and capital depreciation or hours of use are proxies for resource flow.

Methodology: Systematic Literature Review

We conducted a SLR in order to collect a comprehensive sample of empirical studies on farm machinery CPAs in a systematic, transparent, and reproducible manner. While SLRs are now quite common across other disciplines, we are, to our knowledge, the first to apply an SLR to studies on commons management. This SLR approach responds to the main challenge in a study of commons, namely the problem of external validity inherent in case-study methods [START_REF] Poteete | Working together: Collective action, the commons, and multiple methods in practice[END_REF]). In our case, this problem is mitigated through generalising the findings from a relatively high number of studies (N=54) combined with a quality assessment to control for potential selection bias. Our methodological process comprised three major steps: scoping and identification, screening, and coding and evaluation of the final sample (Figure 1). ***Insert Figure 1 about here*** Scoping and identification. We defined the scope by specifying the initial search terms in both English and French. 6 To do this, we first searched private databases and extracted all terms related to machinery sharing agreements in five initial documents. We then searched for these terms in the relevant journals and databases, that is journals related to agriculture and social economy (e.g. Agricultural Economics, Journal of Cooperatives) and field-specific (e.g. AgroDoc, AgEcon) as well as general scientific databases (Web of Science, Scopus, Science Direct, Wiley, and EconLit). Given machinery sharing structures are particularly widespread in France, we also conducted an extensive search of specifically French-language databases (Érudit, Persée, ScholarVox). Finally, because academic publications were scant and to reduce potential publication bias, we investigated the grey literature using Google Scholar and ResearchGate. This first search resulted in the identification of 648 sources.

Screening. The vast majority of identified sources were found to be irrelevant, so we drew up the following inclusion and exclusion criteria: (i) all studies describing types of farm machinery sharing agreements under common property were eligible for the sample; (ii) only studies describing at least the creation of the structure and some membership attributes or institutional characteristics of governance (many records mentioned the arrangement without further description) were included; (iii) only sources written in French or English were considered; (iv) no time or geographical restrictions were applied; (v) a study could be in the form of an article, book chapter, report, or other type of work, but newspaper and web articles were excluded; (vi) all studies on any type of machinery sharing were included with the exception of those on irrigation schemes. 7 In addition, a backward and forward snowballing method was applied after the core body of relevant articles had been identified. This procedure resulted in a final sample of 54 documents covering the 1950-2018 period (see Table A1 in Appendix A). 8

Coding and evaluation. For the purposes of traceability and replicability, we adopted a thorough coding process that clearly links the primary data sources to the analysis. We first selected all the benefit and cost items that occurred repeatedly in the final sample. We then coded each item 1 if it was mentioned in a given study and 0 otherwise. Likewise, we coded each study 1 if it referenced a design principle (O1-O7) or membership attribute (G1-G5) and 0 otherwise (see Tables B1 andB2 in Appendix B). In addition, we assessed the quality of each publication to control for potential biases. First, we checked for the peer-reviewed attribute of each study. We considered that a study complied with the peer-reviewed attribute only if (i) it was in the form A c c e p t e d m a n u s c r i p t of an academic book chapter or (ii) it had either a scholarly publisher with an impact factor at the time of publication or a stated peer-reviewing policy. Second, we checked for any potential conflicts of interest statements in each study. For studies with no statement, we compared the authors' stated affiliations with their research topic [START_REF] Shamoo | Responsible conduct of research[END_REF].

Tables 3 and4 provide a detailed account of the sample composition. Table 3 indicates that the literature on the topic was scarce and that it pertained to a number of social science disciplines, including business, economics, sociology, history, and ethnology. The included studies predominantly covered industrialised countries, especially France (44%). This is unsurprising given the proliferation of CUMAs. Table 4 shows that the majority (52%) of our final sample comprised studies published in peer-reviewed sources by independent researchers. ***Insert Tables 3 and4 about here***

Findings

In this section, we present the findings from our SLR in line with our CPA theoretical approach.

We first identify the costs and benefits of being a member of a farm machinery CPA (4.1) and then explore the institutional and ethical conditions for a CPA to emerge and develop (4.2).

Decomposing the Benefits and Costs of CPA Participation

Based on our SLR, we decompose in Table 5 the various types of benefits and costs underpinning the formulation of our propositions 𝑃 1 and 𝑃 2 .

***Insert Table 5 about here***

The benefits of participating in a CPA can be either direct or indirect. Direct benefits are realmoney advantages that lead to sizable profit increases. These profit increases can result either A c c e p t e d m a n u s c r i p t from huge reductions in mechanisation costs (98%) 9 or from productivity gains (87%), which derive from access to more advantaged technologies at a competitive price. Indirect benefits essentially emerge, on the one hand, from the diffusion of up-to-date technologies, which both improve the working environment and environmentally friendly practices (80%) and reduce risk (59%), and, on the other, from virtuous group dynamics, such as mutual aid (57%) and a "stimulus" effect (22%) (Putterman 1983, p. 82). This diffusion is encouraged through 'learning by doing' processes, which enable farmers to share experiences within their CPA group.

Direct costs are opportunism-free and mostly include timeliness costs, which arise simply because the machinery cannot be in two places at once. These costs, which were reported in the vast majority of the studies (80%), generally increase with the frequency and time-sensitivity of machinery use. They logically peak during high seasonal activities (when all CPA members have the same equipment needs) and sometimes derive from machinery failures brought about by members' lack of skills or training. Historically, timeliness costs have been accorded great significance. For instance, they are deemed to have been the main reason for farm machinery cooperative failures in the 1930s and 1960s in the United States (USDA 1980). Indirect costs result from opportunism [START_REF] Allen | The nature of the farm[END_REF]. While a significant portion of our sample refers to the potentiality of moral hazard phenomena, these are only documented in 39% of the studies. Larsén (2007, p. 23) notes that partnerships "are often characterized by personal relations among the collaborating farmers (friends, neighbours, relatives) and it is reasonable to believe that shirking in effort is more costly in social terms when one has a personal relation to his/her partners at the same time as the level of trust is likely to be higher". However, we cannot exclude the possibility that this relatively uncommon citing of strategic behaviours in our sample derives from the fact that social scientists underestimate the survivorship bias [START_REF] Poteete | Working together: Collective action, the commons, and multiple methods in practice[END_REF]) by focusing on successful institutions [START_REF] Acheson | Institutional failure in resource management[END_REF].

A c c e p t e d m a n u s c r i p t

The Determinants of Cooperation: What Brings Members Successfully Together

Our examination of the benefits and costs related to farm machinery sharing cooperative practices reveals that satisfying the conditions of existence (𝑃 1 ) and expansion (𝑃 2 ) is not necessarily an easy task. Using our theoretical framework, which combines an institutionalist and an ethics approach, we investigated the set of strategies that the CPAs in our study adopted to successfully satisfy these two conditions. Tables 6 and7 practices. This social capital is strongest when it derives from positive previous collaborations between members of the (new) CPA (G2 [50%]). The presence of appropriate leadership, comprising well-integrated, charismatic, trustworthy farmers who are willing to cooperate with their peers, proves crucial in terms of turning the social capital to good account (G3 [44%]).

External situational factors, such as a supportive network (e.g. the CUMA federation in France) and favourable legislation, are also decisive in fostering trust among farmers (O7 [80%]).

Finally, membership homogeneity, in terms of endowments (farm size), interests (farming activities), and cognitive abilities, enhances cooperation in the early stages of a CPA (G5).

A c c e p t e d m a n u s c r i p t

Support for Proposition 𝑃 2 . Once a CPA has formed, trust is sustained by a set of institutional arrangements. Table 6 reveals that very few (9%) of the studies reviewed allude to the item 'graduated sanction mechanisms' (O5). Likewise, few report a breach of a CPA's collectively crafted rules. A combination of three factors may explain these counterintuitive results. First and foremost, 93% of the studies indicate that successful CPAs are groups with clearly defined user and resource boundaries. The degree of formality of the sharing arrangement generally increases as a function of group size (O1). Second, farmers tend to favour small groups, which create a high level of trust (G1 [55%]) through regular face-to-face meetings, direct communication, and informal conflict resolution ("by sitting down right away") (Harris and Fulton 2000c, p. 21), thereby avoiding costly formal procedures (O6 [48%]). Third, the design principle whereby a designated monitor is accountable for a subpart of the commons (i.e. a piece of machinery) vis-à-vis the other CPA members also appears in 35% of the studies. The monitor's role is critical in the event of damage to a piece of machinery because he or she determines whether the deterioration arises from user negligence or obsolescence (O4).

A heterogeneous membership is prone to noisy communication and tensions. At operational level, members display a preference for cooperating with peers who exhibit similar practices to their own concerning the use and maintenance of farm machinery, thereby highlighting the fact that membership homogeneity mitigates collective action costs. Interestingly, in contrast with the oft-mentioned time horizon problem in cooperatives [START_REF] Jensen | Rights and production functions: An application to labor-managed firms and codetermination[END_REF], there is no clear-cut evidence of any negative impact from heterogeneity in member age in terms of level of cooperation. While homogeneity in the membership profile is structurally beneficial for cooperation, it may impede synergies if it is too excessive. As mentioned in 80% of the studies, synergies imply a strong interdependence among members and are only attainable if the CPA has achieved a high level of cooperation. These synergies derive from the farmers' A c c e p t e d m a n u s c r i p t specialisations in technical tasks based on their skills, knowledge, and preferences. CPAs also adopt routines by having specific tasks always performed by the same members to alleviate the coordination costs stemming from interdependence. At the same time, the farmers' withingroup specialisations stimulate group cohesion. On an unrelated note, heterogeneity in farming activities or in soil characteristics helps reduce timeliness costs (G4).

An Ethics Analysis of Collective Action in Farm Machinery CPAs

Support for Proposition 𝑃 1 . The formation of a CPA requires the pre-existence of shared ethical values, including "kinship, personal compatibility, utility, practicality, and reciprocity" (Gröger 1981, p. 173). This is referred to in 69% of the cases. In the French context, which is the best documented, the emergence of CUMAs was marked by a diverse ideological breeding ground that included socialist but primarily Christian-personalist philosophies. For instance, after WWII, "a powerful youth movement gained momentum in [sic] countryside: the 'Jeunesse Agricole Catholique' ([Christian agricultural youth], JAC) […] focussed on the social and economic emancipation of rural youth by getting away from dependence on the traditional relations in which they were rooted" (Herbel et al. 2015, p. 29). Likewise, Pierre (2009, p. 144) reports that "the farming professional movements […] have been, greatly impregnated by the ideology of the JAC, extolling values of cooperation and solidarity between producers in a modernist evolution". Interestingly, in countries that have experienced sudden ideological shifts (such as post-communist Eastern European countries), indifference towards any form of cooperative action is a major obstacle to the creation of farm machinery CPAs. In these contexts, only basic forms of mutual aid among relatives or close friends is achievable (G5).

Support for Proposition 𝑃 2 . When a CPA expands, ethical considerations play a critical role in creating a shared identity. These are expressed in different ways. First, social preferences, predominantly fairness, represent a sine qua non for CPA success. In particular, fairness is A c c e p t e d m a n u s c r i p t instrumental to a membership's ability to cope with one of the major challenges in farm machinery CPAs, that is operation timeliness. In 72% of the studies, well-documented strategies are reported for deciding who has the right to use a piece of machinery when more than one farmer needs it while ensuring fairness among all CPA members. These include randomly drawing the order of use, annual rotation of the starting date for machinery use, and fixing a limited number of hours or acres per use. In this respect, equality appears to be an option in order to avoid conflicts among members, in other words farmers will "go around and do a little bit of everybody's [fields]" (Artz et al. 2010, p. 812). Natural variables may also be used as criteria to determine the sequencing of machinery use because they appear more objective and neutral. For example, physical variations across members' farms (e.g. climate-sensitivity, elevation, soil nature) or agronomic considerations (e.g. crop precocity) may be exploited.

Interestingly, while the choice of allocative strategy (which regularly evolves) may maximise the sense of fairness among the CPA members, it may not necessarily be the best one in terms of economic efficiency (O3). Second, CPA rules are devised locally, consensually, and according to within-group practices. It is also common (65% of the cases) that groups combine formal and informal (i.e. written and unwritten) rules. The legitimacy of the within-group rules derives from a democratic and transparent governance. For example, "with four members, you can expect to get your way one-fourth of the time" (Artz et al. 2010, p. 814). The higher the legitimacy, the higher the compliance with collective rules (O2). Third, the ethical perspective offers a convincing explanation for the low 'graduated sanctions' presence rate (O5 [9%]).

Formal rules are not sufficient and may even be counter-productive for stimulating integrity and cooperative behaviours, as Barthélémy de Saizieu (1984, p. 365) observes: "[some CUMAs] deliberately dispensed with the legal safeguards that usually accompany the cooperative status, thereby reinstating the trust-based relationship among their members that regulated labour exchanges in the past (spontaneity, mutual aid, disinterestedness). […] As non-A c c e p t e d m a n u s c r i p t compliance with the inherent CUMA obligations is no longer punishable by a higher authority, abiding by them becomes a matter of honour" [our translation].

Importantly, the initial set of ethical values that launch a new CPA is not ossified for the whole of the CPA's existence. As suggested by [START_REF] Ahn | Social capital and collective action[END_REF], if the early stages of the CPA are conclusive, the group's axiological cement may strengthen and allow for a supplementary layer of social capital and a reinforcement of its common bond. The CPA members, both individually and as a group, are likely to gain self-confidence and upgrade the social representation of their role not only within the agricultural sector but also in the community and society more broadly. CPAs can act as institutional facilitators that continuously enable members to introduce and share their own ethical values. This catalytic process typically hinges on participatory and democratic procedures. This is the case with the French CUMAs, where the 'one member, one vote' rule applies. Developing values in a collective setting is likely to transform the qualitative nature of the shared resource stock. Indeed, farm machinery cooperatives play an increasingly pivotal role in fostering a more sustainable management of primary production not only by improving farmers' economic situations [START_REF] Artz | Equipment sharing in agriculture[END_REF][START_REF] De Toro | Machinery co-operatives. A case study in Sweden[END_REF] but also by promoting agro-ecological practices and building alternative distribution channels that better comply with consumers' ethical preferences [START_REF] Lucas | Gagner en autonomie grâce à la Cuma. Expériences d'éleveurs laitiers français à l'ère de la dérégulation et de l'agroécologie[END_REF][START_REF] Lucas | Local inter-farm cooperation: A hidden potential for the agroecological transition in Northern agricultures[END_REF]. Along with their positive contribution to the community, CPA members may also enhance their own individuality through their participation in collective action, for example by gaining in autonomy. A significant proportion of the studies reveal that while cooperation brings its own set of rules and norms, farmers often acknowledge that this is a necessary prerequisite for ensuring their autonomy. As noted by Pierre and Thareau (2011, p. 111), "being autonomous also means being less dependent on market fluctuations and changes in public policy and being able to act on these dimensions" [our translation]. Moreover,

A c c e p t e d m a n u s c r i p t

CPAs appear to be a means of fostering the individuality of the most vulnerable by enabling them to cope with a crisis environment, thereby preserving the existence of small farmers in communities [START_REF] Almås | I have seen the future and it works![END_REF][START_REF] Gröger | Of men and machines: Co-operation among French family farmers[END_REF]

(G5).
Finally, approximately half of the studies (43%) stress the importance of leadership. By balancing rule-driven and value-driven leadership, leaders play a key role in all these processes impacting the quantity and particularly the quality of CPAs. As noted by Lanneau (1969, p. 43), leaders are "less chiefs than conciliators", and their mission consists in defusing within-group tensions and fostering moral norms among members. Leaders also act as facilitators, interacting with all external stakeholders likely to increase their CPA's organisational performance (e.g. local government representatives, agricultural advisers, institutional networks) and taking into account the community's aspirations (G3).

Discussion

On Determining Quantity and Quality in Farm Machinery CPAs

We begin by discussing the two factors affecting CPA quantity. Regarding the first factor (i.e. institutional arrangements defining withdrawal policy), our findings indicate that farm machinery sharing CPAs intensively apply some of [START_REF] Ostrom | Governing the commons: The evolution of institutions for collective action[END_REF] updated principles in order to prevent some members from opportunistically overusing the resource. The resource stock boundaries and the resource flow beneficiaries are clearly defined in a combination of formal and informal collectively designed arrangements, which fit with the CPA's specific, local context. However, [START_REF] Ostrom | Governing the commons: The evolution of institutions for collective action[END_REF] cornerstone principle of graduated sanctions is virtually absent from all the studies reviewed. Supplementing the institutionalist analysis with an ethics analysis allows us to understand this surprising finding. In particular, our findings suggest that members manage to cope with operation timeliness (the main issue in farm machinery sharing CPAs) by setting up fair, consensual rules, which reduces the need to design sanction A c c e p t e d m a n u s c r i p t mechanisms. Moreover, our results reveal that some CPAs deliberately dispense with (formal) rules governing their operations in order to stimulate honour and commitment. This echoes the research in ethics showing that in 'prisoner's dilemma' situations, rules (providing for sanctions) may be counter-productive to generating shared moral norms and cooperative behaviours [START_REF] Scalet | Prisoner's dilemmas, cooperative norms, and codes of business ethics[END_REF].

Regarding the second factor (i.e. the size of the resource stock), our findings indicate that the stock's initial size depends on the pre-existing level of trust and social capital, which is made up of previous positive cooperative experiences that may or may not be linked to machinery sharing agreements. Moreover, our analysis unequivocally shows that the resource stock is limited in breadth and depth. In terms of depth limitation, despite the fact farmers in a CPA could potentially reach a 'kibbutz-style' model by increasing their cooperation efforts, there was no evidence of such a fully integrated form in our sample. The main factor impeding full integration appears to be membership heterogeneity-even though member interdependence may partially act as a counterbalancing factor. In keeping with the institutionalist view on cooperative governance (e.g. [START_REF] Abramitzky | Lessons from the Kibbutz on the equality-incentives trade-off[END_REF][START_REF] Burdín | Equality under threat by the talented: Evidence from worker-managed firms[END_REF][START_REF] Hansmann | The ownership of enterprise[END_REF], pushing the CPA resource stock beyond the threshold could undermine the delicate incentive structure that harmonises heterogeneous economic member profiles (i.e. varying degrees of abilities, interests, or endowments). Breadth limitation relates to limited group size, which appears to be a key success factor for CPAs. Relatively small operational scales ensure more effective design and rule enforcement and other more informal institutional arrangements (e.g. shared norms), thereby maintaining a high level of trust and hence a sustainable CPA quantity.

On the question now of how members reach a consensus on quality, we delve into the ethical layer underpinning collective action. Our findings show that the initial quality of the shared resource stock relies on diverse ethical sources, including socialism and primarily Christian A c c e p t e d m a n u s c r i p t personalism. Discovering these two ideologies in this context is unsurprising because they have been influentially "competing and overlapping" throughout the history of cooperation (Menzani and Zamagni 2010, p. 104). Indeed, the very first cooperative, the Rochdale Society, which was established in England in 1844, was marked by a synthesis of these two ideologies [START_REF] Davis | Cooperative values: Change and continuity in capital accumulation the case of the British Cooperative Bank[END_REF]. More generally, this diversity also reflects the idea that "business ethics has its intellectual and historical roots in philosophy and religious ethics" (Greenwood and Freeman 2017, p. 1).

Our analysis also reveals that this initial set of values evolve and may lead the CPA members, individually or collectively, towards the common good. This sense of community can bring about qualitative changes in the CPA, such as a quest for regaining control in relation to market fluctuations and public policies changes, and a shift towards energy self-sufficiency and environmentally friendly practices (Van der Ploeg 2012). These qualitative changes result in an adjustment in the substance of the resource stock and/or in the way of using the existing machinery (e.g. redirecting the use of a tractor towards organic farming). Such qualitative changes are typically possible in CPAs that are arenas favouring democratic and participatory debates. From a Deweyan perspective, such debates enable CPA members to trial actions and evaluate the consequences of these actions on the 'publics' impacted by the CPA, thereby increasing the chances of a positive impact on the community [START_REF] Dewey | The public and its problems[END_REF][START_REF] Sacchetti | Inclusive and exclusive social preferences: A Deweyan framework to explain governance heterogeneity[END_REF].

In this evaluative enterprise, moral leaders appear to play a decisive role by encouraging members to adopt reflexive conduct [START_REF] Gini | Moral leadership and business ethics[END_REF]. One example of this is the French CUMAs, which are thought of as one of the last remaining spaces in which farmers with diverse axiological representations on agriculture maintain dialogue and-to some extent at leastharmonise views [START_REF] Cordellier | Une histoire de la coopération agricole de production en France[END_REF]. However, while such a dialogue process can produce desirable outcomes, a full convergence on ethical values is not necessarily possible, especially A c c e p t e d m a n u s c r i p t when the cooperation level among CPA members is already high [START_REF] Emery | Independence and individualism: Conflated values in farmer cooperation?[END_REF]. In particular, the strong polarisation of farming systems (e.g. technology-intensive factory farms versus family farms) that characterises today's agricultural context in Western countries reflects a lower axiological common denominator among farmers and is likely to complicate any agreement on the qualitative aspects of farm machinery CPAs [START_REF] Bokusheva | Cross-country comparison of farm size distribution[END_REF].

In sum, just as there is a threshold effect on CPA quantity, there is also a threshold effect on CPA quality. This implies that an increase in CPA quantity, while breaking through the quality threshold, is likely to endanger CPA governance. Indeed, if CPA members stop adhering to the business ethics conveyed (implicitly) by the commons, cooperation may be negatively affected.

Using the CPA Approach to Investigate Ethical Issues in Cooperatives

Our CPA framework substantially expands the functional view of cooperatives offered by mainstream economics, which holds that a cooperative remains fixed and essentially restricted to purely economic concerns (e.g. [START_REF] Cook | Advances in cooperative theory since 1990: A review of agricultural economics literature[END_REF]). This idea can be illustrated by tentatively applying our CPA model to a different context, namely credit cooperatives. As suggested by the relevant literature, quantity equates to the total volume of credit (in monetary units) available to borrowers. This combines bank equity (which proxies the resource stock) and the rules governing credit-granting operations that allow bank equity to be maintained [START_REF] Périlleux | Understanding cooperative finance as a new common[END_REF]. However, our approach extends the existing literature by examining the other dimension characterising a banking CPA, that is its quality. The quality of an available loanable monetary unit is affected by credit conditions and the lending technology (i.e. the substance of the resource stock). This captures a first set of ethical issues in credit operations.

For example, setting fair interest rates has strong implications for vulnerable borrowers [START_REF] Hudon | Fair interest rates when lending to the poor[END_REF]). The quality of credit is also strongly dependent on whether and, if so, how much borrowers use the money entrusted to them by the bank for endeavours set up in the pursuit of A c c e p t e d m a n u s c r i p t the common good. This corresponds to a second set of ethical issues, which for instance accounts for novel trends in finance like the nascent field of social banking [START_REF] Cornée | Vive la difference: Social banks and reciprocity in the credit market[END_REF]. More generally, our two-dimensional CPA model explains the recent shift observable in the field of cooperative studies. Cooperatives are no longer seen as organisations focused solely on satisfying their members' interests but increasingly as organisations oriented towards community wellbeing [START_REF] Gui | The economic rationale for the 'third sector[END_REF]. The theorisations of social and community-based have largely contributed to this evolution [START_REF] Borzaga | The emergence of social enterprise[END_REF][START_REF] Peredo | Toward a theory of community-based enterprise[END_REF].

Our two-dimensional framework also captures one of the main cooperative dilemmas, that is the 'cooperation tragedy'. The development of growth strategies by cooperatives to survive in their environment often engenders detrimental ethical consequences, which materialise in loss of membership commitment, degeneration, and demutualisation [START_REF] Jones | Economies of scale versus participation: A co-operative dilemma?[END_REF]. In our CPA framework, this situation characterises a quantity-quality mismatch. The recent waves of mergers among local cooperative banks in Italy-which have brought minor efficiency gains but seriously harmed small-scale, marginalised borrowers-illustrate the ethical risk of prioritising quantity over quality [START_REF] Coccorese | Are mergers among cooperative banks worth a dime? Evidence on efficiency effects of M&As in Italy[END_REF]. However, smallness is not in itself a panacea for aligning the two CPA dimensions. In our study, CPAs benefitting from the presence of a supportive federative network, like the CUMAs in France, clearly appear to encounter less difficulty in intensifying cooperation and in passing the CPA on to the next generation of commoners than those with no such supportive federation (e.g. in the US). Such organisational features are very similar in nature to the initial doctrine prevailing in cuttingedge cooperative experiences like the Raiffeisen Credit Cooperatives, the Mondragon Cooperative Corporation, and the kibbutzim in Israel, which intentionally limited the size of their grassroots organisations while achieving scale economies through coordinating at an upper layer [START_REF] Forcadell | Democracy, cooperation and business success: The case of Mondragón corporación cooperativa[END_REF][START_REF] Guinnane | Cooperatives as information machines: German rural credit cooperatives, 1883-1914[END_REF][START_REF] Ingram | The transfer of experience in groups of organizations: Implications for performance and competition[END_REF]. Thus, CPAs should not be A c c e p t e d m a n u s c r i p t considered in isolation when identifying the organisational features that harmonise quantity and quality. On the contrary, they should be viewed as basic units that pertain to complex systems of polycentric governance, which include nested decision-making levels, federative layers, and the recognition of public authorities [START_REF] Ostrom | Beyond markets and states: Polycentric governance of complex economic systems[END_REF].

Conclusion

This study marks the first step towards a more comprehensive theory of CPAs that aims to adapt the commons paradigm to the realm of cooperatives. Based on a SLR, we use our CPA model to scrutinise the emergence and expansion conditions of multiple farm machinery sharing agreements. The main conclusion from our institutionalist and ethics analyses is that sustainable CPA governance is achievable when members consensually converge on and endorse a quantity-quality equilibrium. However, the existence of threshold effects for both quantity and quality, which result from irreducible member heterogeneity for both economic and axiological reasons, indicates that a CPA thrives when collectivising production assets matches its everevolving membership's ethical preferences and community aspirations.

Our study could be expanded along at least three research avenues. First, the critical issue of membership heterogeneity calls for future qualitative research to examine the harmonisation processes of dissonant individual value systems in collective action [START_REF] Stark | The sense of dissonance: Accounts of worth in economic life[END_REF] and to determine how these processes, when they are democratic, produce desirable outcomes for the community [START_REF] Sacchetti | Inclusive and exclusive social preferences: A Deweyan framework to explain governance heterogeneity[END_REF]. Second, our research highlights the need to conduct multiple case studies and to generalise their findings in order to identify the right scheme of polycentric governance that ensures a convergence on the quantitative and qualitative dimensions of CPAs [START_REF] Pohler | The governance of business federations[END_REF]. The SLR methodology we have introduced to study the commons could be particularly helpful in this endeavour. Third, there is considerable room for further research on While our study focuses predominantly on industrialised countries, farm machinery CPAs represent a promising way of improving quality of life for the world's 500 million smallholders, who account for around 80% of global food production, by both increasing productivity and generating positive externalities for communities [START_REF] Nouwogou | Promouvoir la mécanisation agricole à travers les coopératives agricoles: Cas de CUMAs au Bénin[END_REF]. More generally, although economists have long accused common-property regimes of inefficiency, we can confirm that there is room for collective action and community-based cooperative practices in combination with the private and public spheres as a successful global solution to fair and sustainable development.

A c c e p t e d m a n u s c r i p t 7 Studies on irrigation CPRs, which are better represented in the literature [START_REF] Tang | Institutions and collective action: Self-governance in irrigation[END_REF][START_REF] Wade | Village republics: Economic conditions for collective action in South India[END_REF], may have obfuscated the findings on traditional farm machinery sharing arrangements. 8 These 54 articles are marked with an asterisk in the reference list. 9 Throughout this section, the percentages in parentheses correspond to the prevalence of the item among the studies reviewed. 10 As explained in Section 3.2, our methodology ensures that we have not arbitrarily ruled out any given strategy.

In particular, no item reports strategies that are not described in independently authored, peer-reviewed sources.

  framework, Cox et al. (2010) attest to its relevance and suggest an update of the design principles as follows: (O1) clearly defined users and resource boundaries; (O2) appropriation and provision rules congruent with local social and environmental conditions and with users' benefits proportional to the amount of input required; (O3) collective-choice arrangements; (O4) supervision of the condition of the resource and users' behaviour by monitors who are accountable to the users; (O5) graduated sanctions; (O6) conflict-resolution mechanism; and (O7) minimal recognition of rights to organise. 3

  A c c e p t e d m a n u s c r i p t equipment or to help one another out (if one individual is incapacitated). Machinery rings are associations aimed at coordinating the use of machinery and/or labour among their membership.

  s c r i p t quality measurement. While CPA quantity is by definition easily calculable, the measurement of CPA quality is much more challenging.

  and Benefits from Participating in a Farm Machinery CPA Note: the % column shows the prevalence of each benefit/cost item in the studies reviewed (see TableB1in Appendix B).

Figure

  Figure 1: Methodological Approach

Table 2 about here***

  The categories of mutual aid and machinery rings are excluded from the CPA scope because members have no management or exclusion rights. Mutual aid, which is based on reciprocity between relatives or close neighbours, consists solely of informal arrangements to share

Insert Table 6 about here*** ***Insert Table 7 about here***

  summarise our findings. The prevalence computed for each item (i.e. On and Gn) clearly indicates whether and, if so, how far a particular CPA strategy validates 𝑃 1 and 𝑃 2 . 10 An Institutionalist Analysis of Collective Action in Farm Machinery CPAs Support for Proposition 𝑃 1 . The formation of a new CPA never comes out of the blue. It generally emerges from a pre-existing social capital, which is based either on previous formal or informal machinery sharing agreements or on experience in other types of cooperative

***

Table 1 : Machinery Sharing Agreements around the World

 1

Table 2 : CPAs among Farm Machinery Arrangements Table 3: Descriptive Characteristics of the Sample

 2

*Total > 100% because all appropriate classifications can be selected for a given document.

Table 4 : Quality Assessment Attributes of the Sample

 4

Notes 1 We refer here to the seventh principle of the International Cooperative Association: "co-operatives work for the sustainable development of their communities through policies approved by their members" (Chomel and Vienney 1996, p. 5). 2 In US farms, machinery costs can amount to as much as 41% of annual farm production costs [START_REF] Wolfley | Machinery-sharing contractual issues and impacts on cash flows of agribusinesses[END_REF]. In Quebec, equipment purchasing accounts for 20-25% of total expenses for dairy farmers (Harris and Fulton 2000a). In French farms, mechanisation represents 19% of operating expenses and 29% of fixed assets (AGRESTE 2016).

3 [START_REF] Cox | A review of design principles for community-based natural resource management[END_REF]) splits Ostrom's (1990) principles 1, 2 and 4 into two subcomponents (e.g. 'clearly defined boundaries' becomes 'clearly defined users' boundaries' and 'clearly defined resource boundaries'). Because we also investigated membership characteristics in detail, we decided to merge the subcomponents of these principles into one comprehensive principle (e.g. 'clearly defined user and resource boundaries'). On an unrelated note, Ostrom (1990, p. 90) identifies a further design principle, O8 'nested enterprises', "for CPRs that are part of larger systems". Due to this specific attribute, it is mentioned in our discussion section (Section 5). 4 Agrawal's (2001) article initially considers 'shared norms' and 'homogenous identities and interests' as two different variables. In order to produce a clear framework, we decided to merge these variables because the descriptions of the CPA groups in our sample were generally not extensive enough to address them separately. 5 These forms are not mutually exclusive. Farmers often rely simultaneously on several of them [START_REF] Thomas | Coopération agricole de production: Renouvellement des modalités de coopération de proximité entre agriculteurs[END_REF]. 6 The final search terms were (in alphabetical order): coop* for the use of farm implements; coop* for the use of agricultural equipment; CUMA; farm machinery coop*; joint machinery pool; machinery ring; machinery sharing; machinery-use cooperative; partage de matériel agricole. The variant 'co-operative' was also included.


Thibaud Toullier

Jean Dumoulin

Laurent Mevel

Study and development of an image synthesis software for the simulation of in-situ 3D scenes monitored by infrared cameras

Introduction

Latest improvements on uncooled infrared detectors opens up new perspectives toward the low-cost thermal monitoring of civil engineering's infrastructures. Such monitoring is facing economical, security or even robustness criteria. As a consequence, sizing and placing the measurements means has become critical. In such context, a software that estimates the irradiance received by the sensors of an infrared camera has been developed. This software enables to render the radiative diffuses exchanges between the surfaces of a 3D scene, coming from a CAD (computer-aided design) for example. Thanks to the technological development of 3D animation and processing graphical units of computers, a GPGPU (general-purpose computing on graphics processing units) implementation that reduces the computation time is proposed. In order to take into account the in-situ characteristic of the scene, the software integrates the computation of the solar irradiance both diffuse and direct received at ground. Furthermore, the acquisition system has been considered by implementing a camera model that integrates the optical projection, the digitization and various noises that may affect the measurements. In this study, the developed software will be firstly introduced. Then, a validation of the algorithm for computing the radiative exchanges will be proposed. The software will then be applied to 3D static and dynamic scenes with varying parameters. Finally, prospects on hybrids methods to improve the simulation tool and consider more physical phenomenon are proposed.

Progressive radiosity method for the scene irradiance simulation implemented on GPU

The software enables the rendering of an image of a 3D scene (see Fig. 1), as perceived by an infrared camera. If different methods exist in the literature for solving such problem [START_REF] Shirley | Hybrid Radiosity/Monte Carlo Methods[END_REF]- [START_REF] Wallace | A Two-Pass Solution to the Rendering Equation: A Synthesis of Ray Tracing and Radiosity Methods[END_REF], the classical progressive radiosity method has been chosen for its physical equations solving approach. In its current implementation, the software renders the radiative exchanges between the discretized surfaces of a 3D scene. The thermal properties of the surfaces depend on the wavelength meaning that the rendering is integrated over given spectral bands. The radiosity J k of a surface k that is given by considering its selfemission plus the contribution of the surrounding surfaces j of the scene. After discretization of the equations and for a given spectral band, the following linear equations system is obtained:

J k , Δ λ i =M k , Δ λ i + ( 1-ϵ k , Δ λ i ) ∑ j=1, j ≠ k j =N elements V kj F k → j J j , Δ λ i (1)
Where V kj represents the visibility between the element k and element j, F k → j is the form factor that characterizes the exchange between the surface k and j and ϵ k , Δ λ i is the emissivity of the surface k in the band Δ λ i . The progressive radiosity algorithm has been implemented in C++ by taking advantage of the latest graphical libraries and parallelized through a GPGPU (General-purpose processing on graphics processing units) approach.

1

License: https://creativecommons.org/licenses/by-nd/4.0/deed.en Fig. 1: 3D scene involving a wood house and an infrared camera that can be loaded by the software.

Infrared camera model and detectors

Once the radiosity rendering algorithm has been implemented on accelerated hardware, a camera model has been integrated to simulate the measurements acquisition system. The camera's position, resolution, focal length, aspect ratio, etc. can therefore be customized. The rendering and visualization of the scene is made through this camera model. Furthermore, a detector model from the literature [START_REF] Konnik | High-Level Numerical Simulations of Noise in CCD and CMOS Photosensors: Review and Tutorial[END_REF] has been integrated directly onto the GPU for real-time rendering and visualization. The conversion takes into account the different noises of the acquisition chain (gains, analog to digital conversion, shot noise, etc.).

Solar spectral irradiance

Under the context of civils' engineering structures monitoring, one important aspect to consider for the radiosity balance and in-situ characteristic of the measurement is the sun's contribution. Since the computation is made on a given spectral band, a spectral solar irradiance model was needed. In particular, the SMARTS2 model [START_REF] Gueymard | Simple Model for the Atmospheric Radiative Transfer of Sunshine (SMARTS2) Algorithms and Performance Assessment[END_REF] is fully documented and provides a phenomenological approximation of the solar irradiance received at ground based on the scene's location, date and time that integrates atmospheric standard models to consider the absorption, diffusion and reflexion of the extra-terrestrial radiation as it passes through the atmosphere.

Applications

Error: Reference source not found shows the obtained radiosity maps for a building in a static configuration. One can see that the sun radiation contribution is varying through time. Such simulation is particularly useful to evaluate the impact of the sun, the orientation of the buildings, the materials properties used on urban scenes.

Conclusion

An image synthesis software for the simulation of in-situ infrared thermography measurements 3D scene has been developed. Thanks to its implementation on recent hardware and the use of the latest rendering libraries dynamic scenes can be simulated, as long as a real-time progress rendering and the visualization of the full scene in 3D. Furthermore, the use of sensor models, camera model and atmospheric model from the literature and fully customizable enables an advanced in-situ simulation. As a consequence, advanced study can be performed prior to any exploitation with this software for sizing and placing the camera for example. However, the simulation could be improved, with for example the consideration of optical aberrations for the camera model. Moreover, one last objective will be to compare an infrared thermography measurement of a target made of different characterized materials and controlled in temperature to the simulation data.

Fig. 2 :

 2 Fig. 2: Radiosity map of the wood house for a given day at different hours (from left to right: a 3D view of the model, at 6AM and 12PM).