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This article aims at revealing a CSR model resulting from entrepreneurs' representations in an African context. The discourse of ten entrepreneurs of VSEs established in Cameroon is analysed through the justification and legitimation concepts, coupled with the conciliator mechanism's approach. It appears that in this context, the entrepreneur perceives his/her responsibility situating him/herself simultaneously in three kind of wolrds: the domestic one, the commercial and the spiritual one. The CSR emerging model is three-dimensional. It corresponds to an aggregation of genealogical, geo-economic and spiritual responsibilities, each being respectively anchored in one of the aforementioned worlds. The CSR discourse and practices to be promoted in this continent could be inspired by this model.

Keywords: RSE, TPE (Très Petites Entreprises), mécanisme conciliateur, justification, Légitimation, Afrique subsaharienne/Cameroun, CSR, TPE (Very Small and Small Enterprises), conciliator mechanism, justification, Legitimation, Sub-Saharan Africa/Cameroon, RRSE, TPE, mecanismo conciliatorio, justificación, legitimación, África subsahariana/Camerún

An integrated development program, which includes many soil protection techniques and water harvesting systems, is being implemented in the upstream of Merguellil watershed in order to reduce erosion and improve local population income. This program has modified the spatial distribution of water resources at the watershed scale, increasing its availability in the upstream and reducing it in the plain, located at downstream, where a large area is irrigated from a groundwater aquifer recharged directly from upstream runoff. As a consequence, the economic income derived from irrigated agriculture has been strongly affected, leading to the need to target the level of soil erosion reduction. By coupling a hydrological model to an economic optimization model MOTAD Target, this work has simulated the impact of different scenarios of reducing soil erosion in the upstream on the improvement of local population income and the evolution of economic return of farmers in the plain. The simulated scenarios are to reduce erosion by 25%, 50% and 75%. The results showed that all simulated scenarios lead to additional benefits for population in the upstream area. In contrast, they result in losses of economic income for farmers in the downstream area (plain). These losses become highly significant beyond the scenario of reducing erosion by 50%. The global economic income generated throughout the watershed (upstream and downstream) also decreases with the level of soil protection. This means that economic gains obtained in the upstream can only partially compensate the lost benefits in the downstream, due to the diminution of groundwater recharge. Our simulations suggest targeting the reduction of soil erosion and show that, in the case of Merguellil watershed, the optimal compromise solution between the three objectives (economic, social and environmental) is situated in the range of scenarios corresponding to a reduction of erosion by 25% and 50%.

Keywords: érosion, distribution, amont, aval, revenu, gain, perte, compromis, erosion, water distribution, upstream, downstream, income, gains, losses, compromise

Lake Bastani (Corsica, France), a small alpine lake (2089 m), is located in a pristine rocky watershed. It presents some characteristics of eutrophic lakes, whereas four other similar lakes are oligotrophic or ultraoligotrophic. Moreover, at the beginning of the century it was described as being oligotrophic.The lake is ice-covered from November to June. Intense phytoplankton activity begins before the ice melts completely and goes on until fall freezing. Consequently Secchi disk transparency is between 3.2 m in June and 1.8 m in August. The algal biomass, as expressed by chlorophyll-a content, is maximum at the bottom. Chlorophyll-a is about 4-5 mg-m-3 at ice melting and reaches a maximum of 46 mg.m-3 in August. Primary production is highest in the upper levels of water with 41 mg.C.m-3.d-1 at - 5 m. These values are 20 to 80 times that of the other Corsican lakes. Regarding the different trophic classifications this lake presents some features of eutrophic lakes.In 1923 a survey of phytoplankton by Pestalozzi showed that the lake was oligotrophic. This trophic evolution is therefore recent; it is shown by the complete disappearance of Desmidiaceae, the near disappearance of Diatoms, the appearance of green algae with Oedogonium and Spirogyra dominant in summer and autumn, and the development of blue-green algae with Oscillatoria.The seasonal pattern of phytoplankton composition displays diatom development at ice- and snow-melting with the green algae Oedogonium. During the summer warmth, green algae are dominant with the blue-green Oscillatoria. Green algae Oedogonium and Spirogyra increase until the fall turnover.The lake is 2nd-order dimictic with two turnovers in spring and autumn, and two periods of thermal stratification. A strong and frequent wind stirs the lake water inducing homogeneisation of the epilimnion and sometimes the disappearance of the hypolimnion. Dissolved oxygen is always present even at the bottom where O2 saturation is about 50% in winter. Nitrogen is very low - 0.01-0.04 mg.l-1 N-NO3 - and phosphorus (PO4) is below the detection level in the epilimnion during summer, due to intense phytoplankton activity, The hypolimnion is richer in NH4, NO2 and PO4. In spring when the snow begins to melt the surficial waters are enriched with N (NO3 + NH4) and P-PO4, showing the contribution of concentrated snow water.In fact atmospheric input is the dominant external loading in such a watershed. Nitrogen atmospheric input is extrapolated from data obtained at Lake Bavella 30 km southwards for 3 years - 1984 to 1986. The dissolved inorganic nitrogen input is about 0.8 g.m-2 .y-1 , equivalent to wastes from some 30 permanent inhabitants for the whole watershed, About 80 % of annual rainfall is stored in the snowpack, as are ¾ of the dissolved inorganic nitrogen. This nitrogen returns to the lake during a period of about one month which represents 100 kg and a loading of 80 mg.m-2.d-1 for 30 days; it is equivalent to wastes from some three hundred capita during one month. Moreover it is known that the first melwaters are considerably enriched with several ions, especially those of ecological concern, H+, SO4--, NO3¯, NH4+. Using findings from literature we can estimate that in the first two weeks of melting, up to half the annual atmospheric input of dissolved inorganic nitrogen reaches the lake with meltwater concentrations of more than 1 mg.N.l-1. The total dissolved nitrogen input is estimated at 1.2 g.m-2.y-1 and the total nitrogen input at 1.3 g.m-2 .y-1.No data are available for the phosphorus atmospheric input but estimations from literature are about 10 mg.m-2 .y-1 for orthophosphate and 60 mg.m-2 .y-1 for total phosphorus. The release of P-PO4 from the melting snowcover and from ice, added to the tremendous release of inorganic nitrogen, explains the start of vigorous phytoplankton production before the ice melts completely. By this early start primary production may avoid the flush of nutriments resulting from the flow of melting water.Trophic conditions in Lake Bastani are a matter of question as the other four lakes studied with the same edaphic conditions are oligo- or ultraoligotrophic. A comparison between Lake Bastani and the ultraoligotrophic Capitello Lake, which has the same geomorphological and ecological environment, reveals the determining factors of this paradoxical situation, though a nutrient budget is still not available.A low flushing rate (17 months) cannot be the explanation, as that of Lake Capitello is similar (12 months).The external loading (from watershed and atmosphere)being the same, the difference between the two lakes is to be found in the internal loading.The fact that Lake Capitelto and the other oligotrophic lakes present notable N concentrations in summer (0.2-0.3 mg.l-1 ), when Bastani displays N- concentrations 10 times lower, is a sign that they are limited in phosphorus. Conversely Lake Bastani is not phosphorus-limited.The determining factor in this situation seems to be windstirring. Lake Bastani is downwind of a pass in the axial range of Corsica and is submitted to strong frequent winds. Windstirring induces an epilimnion homogeneisation, the downward migration of the thermo- and chemoclines. Thus phosphorus from the sediments can be transferred to the photic zone and is not limiting for phytoplankton. Phytoplankton exhausts nitrogen which is very low at the end of summer. In Lake Capitello as in the other lakes, shielded from the wind by rockwall screens, no mixing occurs, phosphorus cannot be supplied from the sediments and is limiting : nitrogen is not used up and remains at relatively high levels of 0.2-0.3 mg.l -1.Recent eutrophication cannot be explained by an increase of nutrient availability from the sediments due to windstirring, as no climatic change has occurred in the fast century. The probability that internal loading had reached a threshold by progressive accumulation of nutrients in the sediment is very slight if there is no change in the external loading (the unique source of "new" nutrients) and/or the trophic status of the lake. Thus an increase in the external loading seems to be responsible for the eutrophication of Lake Bastani. The atmospheric inupt is the only external reason for a change in the nutrient rate. An increase in the phosphorus atmospheric input by local (forest fires) and regional (long range pollution) human activities is suspected, but does not seem sufficient to change the trophic status of the lake as it has no effect on other lakes, which remain oligotrophic. Moreover, atmospheric P loading is well below the level of phosphorus release from sediments, as estimated from literature. Conversely, an atmospheric inorganic nitrogen input has increased at least twice due to long range pollution (agricultural, industrial and domestic activities). This was estimated from a typologic classification of rain events in Corsica. This increase in atmospheric nitrogen loading might explain the change in the trophic status of the lake, N having been limiting. In the other P-limited lakes the increased atmospheric N input has only increased the N-NO3 concentration in lake water. This explanation being the most realistic, it is of great interest to note that long range atmospheric pollution could induce the eutrophication of a pristine oligotrophic lake.

Keywords: Alpine lake, eutrophication, atmospheric pollution, pristine watershe, Corsica

The hydraulic models that are used to simulate floods in rural areas are not adapted to model floods through urban areas, because of details that may deviate flows and create strong discontinuities in the water levels, and because of the possible water flow running in the sewage network. However, such modelling is strongly required because damage is often concentrated in urban areas. Thus, it is necessary to develop models specifically dedicated to such floods. In the southern part of France, rains may have a high intensity but floods generally last a few hours. During extreme events such as the October 1988 flood in the city of Nîmes, most of the flow remained on the ground with high water depths and high velocities, and the role of sewage network can be neglected. A 1-D model and a 2-D model were used to calculate such flows, which may become supercritical. On the catchments of the streams which cross the city of Nîmes, the rainfall was estimated as 80 mm in one hour and 250 mm in six hours in October 1988, although some uncertainties remain. The return period can be estimated between 150 and 250 years. The zone selected to test the models was an area 1.2 km long and less than 1 km wide in the north-eastern part of the city. It includes a southern part with a high density of houses. The slope from the North (upstream) to the South (downstream) was more than 1 % on average and was decreasing from North to South. Various topographical and hydrological data were obtained from the local Authorities. The basic data were composed of 258 cross sections of 69 streets with 11 to 19 points for each cross section. Observations of the limits of the flooded areas and of the peak water levels at more than 80 points can be used to validate the calculation results. The inputs consisted of two discharge hydrographs, estimated from a rainfall-discharge model from rains with a return period of 100 years, which may result in an underestimate of these inputs. These two hydrographs correspond to the two main structures that cross the railway embankment, which constitutes an impervious upstream boundary of the modelled area. Whereas the western and eastern boundaries are well delimitated by hills above maximum water levels, the downstream southern boundary is somewhat more questionable because of possibilities of backwater and inflows from neighbouring areas.The 1-D software REM2U solved the Saint Venant equations on a meshed network. At crossroads, continuities of discharge and of water heads were set. The hydraulic jump was modelled by a numerical diffusion applied wherever high water levels were found. The Lax Wendroff numerical scheme was implemented. It included a prediction step and a correction step, which implied precise solving of these very unsteady and hyperbolic problems. The software was validated on numerous test cases (Al Mikdad, 2000) which proved the adaptation to problems of calculations in a network of streets.The 2-D software Rubar 20 solves 2-D shallow water equations by an explicit second-order Van Leer type finite volume scheme on a computational grid made from triangles and quadrilaterals (Paquier, 1998). The discontinuities (hydraulic jumps for instance) are treated as ordinary points through the solving of Riemann problems. For the Nîmes case, the grid was built from the cross sections of the streets. Four grids were built with respectively 4, 5, 7 or 11 points for every cross section and these points correspond to the main characteristics of the cross section: the walls of the buildings, the sidewalks, the gutters and the middle point. The simplest crossroads were described from the crossings of the lines corresponding to these points, which provide respectively 16, 25, 49 or 121 computational cells. The space step was about 25 metres along the streets but went as low as 0.1 m in the crossroads; due to the explicit scheme, which implies that the Courant number was limited to 1, the time step was very small and a long computational time was required.The computations were performed with a uniform Strickler coefficient of 40 m1/3/s. Both 1-D and 2-D models provided results that agreed well with observed water levels. The limits of the flooded area were also quite well simulated. However, locally, the differences between calculated and observed maximum water depths were high, resulting in an average deviation of about 1 metre. The reasons for such deviations could come from three main causes. First, the uncertainty of topographical data is relatively high, because of the interpolation between measured cross sections without a detailed complementary DEM (digital elevation model). Second, the observed levels were also uncertain and reveal local situations that are not reconstructed by the hydraulic models which provided maximum water levels averaged on one cell which may not coincide with the exact location of the observations. Finally, modelling means a simplification of the processes, which implies cancelling the level variations due to some obstacles, such as cars, which are not simple to identify.In conclusion, both software packages can model a flood, even a flash flood, in an urbanised area. Research is still necessary to develop methods to fully use urban databases in order to define details more precisely. The improvements to the 1-D software should include a better modelling of storage and of crossroads with an integration of adapted relations for the head losses. 2-D software has a greater potential but the difficulty to build an optimal computational grid means a long computational time, which limits the use of such software to small areas. For both software packages, methods still need to be developed in order to represent exchanges with the sewage network, storage inside buildings and inputs directly coming from rainfall.

Keywords: Flash floods, urban risk, hydrodynamic modelling, de Saint Venant equations, october 1988 Nîmes flood, 1-D software, 2-D software, hydraulic jump

The dammed up marshes of the French Atlantic coast cover about 200 000 ha between River Vilaine and the « Bassin d'Arcachon ». Eighty eight % are managed with freshwater. They constitute original environments initially created for agriculture or for salt production, and they are now threatened by land abandonment within the next decade. Concurrently to aquaculture (in created or existing ponds), exploitation of the fish stocks in the ditchweb is likely to encourage a diversification of agricultural activities. Unfortunately, bibliographic analysis reveals the relative scarceness of research about sampling methods and qualitative or quantitative characteristics of these fish communities. This is quite surprising considering the importance of the ditchwed of this kind of environment outlined by several authors. In the Netherlands, BELTMANN (1984) assessed that there is a total of 400 000 km of ditches. In France, the littoral dyked marshes of the Atlantic coast couid comprise 20 000 km of ditches and about 24 000 ha of open water. The present work provides for the first data on the fish community of Bourgneuf marsh.The northern part of the marsh of Bourgneuf, 2 700 ha provided whith f reshwater, contains nearly every kind of landscapes found throughout the whole Breton-Vendéen marsh. The pattern of the ditch network strongly changes from a zone to another (fig.1) : presence of former salt pans in the western part, regular geometric shapes in the recently created polders next to the River Falleron, irregular ditchweb pattern in the eastern part. The average density of the ditch network is 91 m of ditches per ha, totalizing 234 km in the study area. The total surface of open water, composed of ditches and basins (former salt pans), covers 411 ha (over 15 % of the study site). Diversity of ditch types occurs at fine scales (<1 000 m2), they vary according to their widths (0,3 to 7 m), depths (average, 42 cm; SD, 20,4), thickness of silt layer (average, 43 cm; SD, 42) and their hydrophyte vegetation cover (average, 70 %; SD, 60 %). As a consequence of this heterogeneity, available habitats are scattered over the marsh (mosaïc distribution). A nested sampling (FRONTIER, 1983) was carried out to take into account this high heterogeneity : 5 sampling areas were selected randomly. In each one, 3 to 5 ditches were chosen according to their characteristics (see above). Sampling stations were delimited by 2 stop nets (5 mm mesh) settled 30 m apart, in order to avoid fish migration. Field work was conducted using « Heron » electric fishing material (see LAMARQUE et al., 1978). In each ditch-section, we carried out as many successive catches as necessary to apply the maximum likelihood weighted estimation method of CARLE and STRUB (1978). Nine to 19 stations were sampled at 5 periods, between 1987 and 1989. A total of 74 samples were collected.The fish community was composed of 21 species (table 1) and corresponded to the bream zone of Verneaux's classification (1977). The densities and biomass were quite high (on average 315 kg/ha and 11 460 fishes/ha) but very variable (0 to 2 120 kg/ ha and 0 to 39 300 fishes/ha). The catfish, Ictalurus nebulosus (170 kg/ha), the eel, Anguilla anguilla (47 kg/ha) and the tench, Tinca tinca (28 kg/ha), represented on average 77,5 % of the standing crop, but their spatial distribution was very irregular. These estimates are assumed to be reliable considering that the data used for the calculations were provided by a sampling design which permits to respect the basic assumptions of the removal method. (f) The population size could only change because of the fishings (no migration because of the stop nets; no recruitment/death because of the short duration of the fishing sequences). (ii) The standard sampling design permitted to reduce the variations of the catch probabilities between the successive removals. Several studies have shown that this removal method under-estimates by about 20 % the true size of the fish populations (e. g. BOHLIN and SUNDSTROM, 1977; MAHON, 1980). But they were based on Zippin's method, and the estimator of CARLE and STRUB (1978), that we used, was shown to be more robust (COWX, 1983; GERDEAUX, 1987). Nevertheless, we assume that the values presented in this paper provide for an approached information on the sizes of the studied fish populations.To assess the fish-habitat relationship, a correspondence analysis (fig. 2) was performed on the 74 samples X 17 species matrix (excluding the sticklebacks, Gaslerosteus aculeatus and Pungitius pungitius, which population size estimations failed because of their low catchabilities). Four groups of samples were ordinated according to their specific richness and the species they contained. Several habitat parameters were projected on F1-F2 factorial map (fig. 3). Hydrophyte cover, thickness of silt layer, water depth (fig. 3 and 4), which are directly controlled by human maintenance, appeared to be the major structuring habitat parameters for the fish community. In the deepest and less silted stations, the communities were rich (on average 11 species; group 4, fig. 2). Predators such as pike-perch, Stizostedion lucioperca, and perch, Perca fluviatilis, occurred, and cold water species were found, such as minnow, Phoxinus phoxinus, or chub, Leuciscus cephalus. When the silt layer was thicker and the water level was intermediate, the specific richness decreased (average, 6,2 species) and the community was either dominated by the cattish (group 2, fig. 2) or by the rudd, Scardinius erythrophtalmus (group 3, fig. 2), according to the importance of the aquatic vegetation cover. Habitats with thickest silt layers, shallowest waters and maximum aquatic vegetation cover contained the poorest communities (average 3,9 species) dominated by eel (group 1, fig. 2). There is also evidence that the diversity of the community has progressively decreased since 1987 (fig. 5). The most stenothermous species disappeared, and the importance of the catfish increased : it doubled between May 1987 and September 1989 (fig. 6). Although the eel is the species most adapted to this environment, we emphasize the diminution of its biomass (fig. 7). These phenomena could be partly due to the climate (cold winter in 1987, important swelling in January 1988 and 2 droughts in summers 1988 and 1989). But they are mainly caused by the water management policy which is intended to favour agriculture by keeping stable water levels (evacuation of swellings) and by preventing the freshwater part from the marine influence (collective sluice gates). This does mot permit an optimal breeding of the species that have to spawn on flooded meadows, neither a proper colonisation of the marsh by elvers.

Keywords: Marais littoral endigué, marais Breton-Vendéen, peuplement piscicole, Anguilla anguilla, Ictalurus melas, densités, biomasses, répartition spatio-temporelle, habitat, gestion hydraulique, Breton-Vendéen marsh, dyked marsh, coastal wetland, fish community, Anguilla anguilla, Ictalurus melas, density, biomass, spatio-temporal distribution, habitat, water management

AbstractThe transnationalization of collective action involves the rescaling of social movement activity. Scale and the politics of scale have received little attention from sociologists and political scientists. They are, however, central to Anglo-Saxon critical geography, where they have spurred the development of an emergent field of research on transnationalization. This article aims at making visible the theoretical developments and programmatic orientations of this body of work. Attention is directed towards processes of construction of a transnational scale of organisation and movement activity, the multiscalar character of transnational collective action, and the enduring role of « place » in the upscaling of collective framings.

This study examines the trajectories of appropriation of a CSR program by SMEs' owners. It is based on the theoretical and conceptual framework of appropriation developed by De Vaujany (2005), with particular attention to the mechanisms at work. In this qualitative and exploratory research, the authors analyse the experience of four SME's owners who took part in the CSR program proposed by the CJD network, an association of young managers. Each SME owner was questioned about the reasons of his participation in the CSR program and the way he experienced this responsible collective action. The results of this research lead the authors to distinguish two different appropriation dynamics : a dynamic of awareness and another dynamic of commitment, according to socio-political but also cognitive mechanisms.

Keywords: Performance, RSE, PME, Appropriation, Performance, CSR, SME, Appropriation, Performancia, RSE, PyME, Apropiación

The purpose of the present paper is to move closer to two registers of knowledge : SMEs' offshoring and SMEs' networks. In order to, the Uppsala model and isomorphism concept to highlight the role of networks, inter-organizational or interpersonal, on SMEs' offshoring decisions.This analysis of the literature will be confronted to a qualitative study realized on two SMEs belonging to the same network.The results shows that networks can encourage a SMEs' offshoring-induced via a mimetic isomorphism and can stop this strategy via a coercive isomorphism.

Keywords: Effet réseau, PME, Délocalisation, Modèle Uppsala, Isomorphisme, Network effects, SMEs, Offshoring, Uppsala model, Isomorphism, Efecto de red, PyME, Deslocalizacion, Modelo de Uppsala, Isomorphismo

The confinement of populations decided to deal with Covid-19 has caused an economic crisis whose effects are not fully known. Indeed, if the crisis can cause threats, it can also generate opportunities. Also, the objective of this research is to study the impact of the Covid-19 crisis on the informal sector in Africa. The results of a survey of 164 entrepreneurs in Cameroon show that the crisis has a positive impact on the creation of informal businesses and has encouraged the adoption of informal practices by formal businesses. Moreover, while in most countries, as in previous crises, government stimulus measures are based mainly on the formal sector, public management of the pandemic in Cameroon is marked by support and support measures. Support for the informal sector, but also through greater tolerance of these activities and practices. However, while this attention is surprising and appreciable, given its weight in the economy, the fact remains that no country can achieve the desired development by relying solely on informal activities. In this sense, the dynamic of informalization observed should worry and challenge the public authorities.

Keywords: Covid-19, Crise économique, Secteur informel, Opportunité, Menace, Covid-19, Economic crisis, Informal sector, Opportunity, Threat, Covid-19, Crisis económica, Sector informal, Oportunidad, Amenaza

This study examines the ability of women entrepreneurs in Burkina Faso to sustain their business in the formal trade and services sector, as they face different forms of subordination and exclusion, the complex articulation of which has not yet been clarified (Marlow, 2019). As women, they have to negotiate the masculine norms of the formal sector. As an established businesswoman, they are at odds with survivalist female norms that have real legitimacy in the country. In this context, how do they navigate between these two gender regimes? Our interpretative approach compares what women say they do to sustain their business with how they comment on their actions. We show that they manage to make the most of both male and female entrepreneurial worlds. This navigation is possible because they work with, adhere to and distance themselves from both the masculine norms of the formal sector and the feminine survivalist norms. However, in this double game, they experience a sense of incongruity and duplicity with both communities. This can limit many of the exchanges that would allow them to make more sense of what they have undertaken to nurture a strategic vision.

Keywords: Genre, Pérennité entrepreneuriale, Afrique subsaharienne, Subordination et insubordination, Gender, Entrepreneurial sustainibility, Sub-Saharan Africa, Subordination and insubordination, Género, Sostenibilidad empresarial, África subsahariana, Subordinación e insubordinación