bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbial Strategies for Cellulase and Xylanase Production through Solid-State Fermentation of Digestate from Biowaste
Authors: Mejias Laura , Cerda Alejandra , Barrena Raquel , Gea Teresa , Sánchez Antoni
Published: July 2018

Solid-state fermentation (SSF) is a promising technology for producing bioproducts from organic wastes. The objective of this study is to assess the feasibility of using digestate as substrate to produce hydrolytic enzymes, mainly cellulase and xylanase, by exploring three different inoculation strategies: (i) SSF with autochthonous microbiota; (ii) non-sterile SSF inoculated with Trichoderma reesei and (iii) sequential batch operation to select a specialized inoculum, testing two different residence times. Native microbial population did not show a significant cellulase production, suggesting the need for a specialized inoculum. The inoculation of Trichoderma reesei did not improve the enzymatic activity. On the other hand, inconsistent operation was achieved during sequential batch reactor in terms of specific oxygen uptake rate, temperature and enzymatic activity profile. Low cellulase and xylanase activities were attained and the main hypotheses are non-appropriate biomass selection and some degree of hydrolysis by non-targeted proteases produced during fermentation.
Lost in Transition? Directions for an Economic Geography of Urban Sustainability Transitions
Authors: Fastenrath Sebastian , Braun Boris
Published: July 2018

Socio-technical transitions towards more sustainable modes of production and consumption are receiving increasing attention in the academic world and also from political and economic decision-makers. There is increasing demand for resource-efficient technologies and institutional innovations, particularly at the city level. However, it is widely unclear how processes of change evolve and develop and how they are embedded in different socio-spatial contexts. While numerous scholars have contributed to the vibrant research field around sustainability transitions, the geographical expertise largely has been ignored. The lack of knowledge about the role of spatial contexts, learning processes, and the co-evolution of technological, economical, and socio-political processes has been prominently addressed. Bridging approaches from Transition Studies and perspectives of Economic Geography, the paper presents conceptual ideas for an evolutionary and relational understanding of urban sustainability transitions. The paper introduces new perspectives on sustainability transitions towards a better understanding of socio-spatial contexts.
A Fuzzy Adaptive PID Controller Design for Fuel Cell Power Plant
Authors: Qin Yuxiao , Sun Li , Hua Qingsong , Liu Ping
Published: July 2018

Solid oxide fuel cells (SOFCs) are promising electrochemical devices which translate chemical energy directly into electric energy with high efficiency and low pollution. However, the control of the output voltage of SOFCs is quite challenging because of the strong nonlinearity, limited fuel flow, and rapid variation of the load disturbance. Nowadays, proportional-integral-derivative (PID) controllers are commonly utilized in industrial control systems for their high reliability and simplicity. However, it will lead to overshoot and windup issues when used in the wide-range operation of SOFCs. This paper aims to improve the PID controller performance based on fuzzy logic by (1) identifying a linear model based on the least squares method; (2) optimizing the PID parameters based on the generated linear model; and (3) designing a fuzzy adaptive PID controller based on the optimized parameters. The simulation results of the conventional PID controller and the fuzzy adaptive PID controller are compared, demonstrating that the proposed controller can achieve satisfactory control performance for SOFCs in terms of anti-windup, overshoot reduction, and tracking acceleration. The main contribution of this paper can be summarized as: (1) this paper identifies the SOFC model and uses the identified model as a control object to optimize conventional PID controllers; (2) this paper combines a fuzzy logic control scheme and PID control scheme to design our proposed fuzzy adaptive PID controller; and (3) this paper develops an anti-windup structure based on a back-calculation method to reduce saturation time and overshoot.
Numerical Simulation and In-Situ Measurement of Ground-Borne Vibration Due to Subway System
Authors: Yang Jinping , Li Peizhen , Lu Zheng
Published: July 2018

A coupled finite element–infinite element boundary method performed by the harmonic analysis based on the commercial software ABAQUS was verified by comparing it with the thin layer method to address the issue of subway induced vibration, a major environmental concern in urban areas. In addition, an interface program was developed to automatically read the simulation result files in the harmonic analysis, and then put the data into MATLAB, achieving the frequency domain analysis. Moreover, a site measurement was performed on a practical engineering track bed-tunnel lining-surrounding formation located on Line 2, Shanghai Metro and rich vibration data were acquired. Then, the corresponding simulation model was established and the numerical results were compared with the measured data based on the developed program, which was verified applicable for the practical engineering of subway induced vibration on the soft site. The proposed prediction formula of the vibration level, by comparison with the measurement, is applicable for the prediction in subway induced vibration. The results show that there exists a vibration amplifying zone a certain distance to the tunnel under high frequency loads due to the wave propagation and reflection. Finally, a parametric study was conducted in an elastic half-space simulation to investigate the influence of model widths and depths with infinite element boundary on the numerical results. The higher performance of the combined finite element–infinite element boundary method, which can decrease the model sizes in widths and heights 50% effectively, was demonstrated. Consequently, the coupled finite element–infinite element boundary method and developed frequency analysis with interface program provide rational numerical methods for the models of subway induced vibration.
Stage Classification and Characteristics Analysis of Commercial Gentrification in Seoul
Authors: Yoon Yoonchae , Park Jina
Published: July 2018

Recently, local shops and small houses in Seoul have been converted to cafes, western style restaurants, and large chain stores. These changes, recognized as commercial gentrification in residential areas, are now a big issue in Korean society. This phenomenon has some positive effects, such as the emergence of new consumption spaces and improved neighborhood images. However, this study concentrated on changes in regional characteristics, landscape, and industry homogenization. This study demonstrates the presence of a cyclical environmental change process commonly identified in areas of gentrification and identifies characteristics of individual stages of the gentrification process. The results indicate that medium-scale local stores in Stage 1 changed to small-scale food and beverage businesses in Stage 2. Then, in Stage 3, they changed to large-scale clothing retailers. In particular, the process of change from Stage 2 to Stage 3 revealed that, as the diversity of business types decreases, their uses change and the proportion of chain stores increases. In other words, although Stage 2 has the highest level of mixed use and density, indicating the greatest level of vitality, commercial gentrification to Stage 3 results in decreases in use, the number of aged buildings, and density. Thus, Stage 3 can be identified as the stage in which streets lose their vitality, as suggested by Jacobs. To maintain street vitality, it is suggested that commercial district management occurs during the transformation from Stage 2 to Stage 3 of commercial gentrification.
Systems Thinking Education—Seeing the Forest through the Trees
Authors: Koral Kordova Sigal , Frank Moti , Nissel Miller Anat
Published: July 2018

Systems thinking is an indispensable tool in comprehending and analyzing real-world phenomena. Observed processes are naturally composed of many interconnected components which ought to be studied jointly rather than individually. Engineering systems thinking is a very valuable skill, which helps to successfully execute multi-disciplinary projects. In high-tech companies that deal with complex and dynamic systems projects, the need for engineers with high systems thinking skills is growing. Engineers with high systems thinking skills are able to understand the big picture and the project in its entirety, both functionally and conceptually, without necessarily knowing all of the small details. Systems thinking enables understanding the entire system beyond its components, and clarifies the importance of the isolated component as part of the system as a whole. Systems thinking helps understand how sub-systems connect to one whole system, and provides solutions for the client’s specifications and requirements. In addition, systems thinking enables perceiving the inter-relationships and mutual influence among the system’s components and other systems. The current study examined the development of systems thinking among engineers and engineering students. In addition, the personality traits of engineers with high systems thinking skills were examined by the Myers-Briggs Type Indicator (MBTI) personality type test. This article also presents the initial results of the development of a new systems thinking study course, taught as a pilot course to industrial and management engineering students. It seems that engineers with certain personality traits can acquire or improve their systems thinking capabilities through a gradual, long-term learning process and by acquiring the necessary tools. Additionally, the study includes recommendations for the continuation of ongoing research on developing systems thinking.
Willingness to Pay for Recreational Benefit Evaluation in a Wastewater Reuse Project. Analysis of a Case Study
Authors: Paola Verlicchi , Mustafa Al Aukidy , Giacomo Zanni
Published: July 2018

The study deals with the evaluation of the recreational benefit of a reclaimed water reuse project in the municipality of Ferrara, north Italy, by means of the contingent valuation method. It also provides an analysis of the public acceptance of the project, determined by eliciting the willingness of the local people to contribute to the realization of this project in monetary terms (their willingness to pay). The project involves the upgrade of the existing wastewater treatment plant by conventional (rapid sand filters) and natural (constructed wetland) treatments. The latter will be constructed within the urban park surrounding the wastewater treatment plant area and will combine the objectives of both wastewater treatment with recreational services, since they will create equipped green areas open to the public. The study is based on the answers provided by 400 respondents, who are residents in the four districts of the municipality of Ferrara. It emerges that willingness to pay is strongly influenced by the socio-economic characteristics of the respondents, with an amount on average of 48 €/family.
Applicability of a Spatially Semi-Distributed Hydrological Model for Watershed Scale Runoff Estimation in Northwest Ethiopia
Authors: Zelelew Demlie G. , Melesse Assefa M.
Published: July 2018

Estimation of runoff is vital forplanning activities in relation to integrated watershed management and flood protection measures. This research was conducted at one of the catchments in Abbay River (upper Blue Nile River) basin to assess the applicabilityof the Hydrologic Engineering Centre Hydrological Modelling Software (HEC-HMS) modelfor simulation of runoff. It was aimed at selecting the best loss and transform methods in the model, as well as testing the applicability of the calibrated model to ungauged watersheds. Two loss methods such as soil conservation service (SCS) and initial and constant methods with two transform methods including SCS and Clark unit hydrographs were considered in the study for selecting the best combinations applicable in the area. While comparing the simulation results of each combination, better results were obtained in the model set containing the initial and constant loss method and SCS unit hydrograph with a Nash-Sutcliff Efficiency (NSE) of 82.8%, R2 of 0.83, and 10.71% of relative bias errors, followed by initial and constant with Clarks unit hydrograph, and it can be used for similar ungauged watersheds.
Anthropogenic Reservoirs of Various Sizes Trap Most of the Sediment in the Mediterranean Maghreb Basin
Authors: Sadaoui Mahrez , Ludwig Wolfgang , Bourrin François , Bissonnais Yves Le , Romero Estela
Published: July 2018

The purpose of this study is to obtain a spatially explicit assessment of the impact of reservoirs on natural river sediment fluxes to the sea in the Mediterranean Maghreb Basin (MMB), a region where both mechanical erosion rates and the anthropogenic pressure on surface water resources are high. We combined modeling of riverine sediment yields (sediment fluxes divided by the drainage basin area) and water drainage intensities in a 5’ × 5’ grid point resolution (~10 km × 10 km) with a compilation of existing reservoirs in the area, and calculated sediment trapping based on average water residence time in these reservoirs. A total number of 670 reservoirs could be assembled from various sources (including digitization from Google maps), comprising large-scale, small-scale and hillside reservoirs. 450 of them could be implemented in our modeling approach. Our results confirm that natural sediment yields are clearly above the world average, with the greatest values for Morocco (506 t km−2 year−1), followed by Algeria (328 t km−2 year−1) and by Tunisia (250 t km−2 year−1). Including dams in the downstream routing of suspended sediments to the sea reduces the natural sediment flux in the entire MMB to the sea from 96 to 36 Mt km−1 year−1, which corresponds to an average sediment retention of 62%. Trapping rates are highest in the Tunisian basin part, with about 72%, followed by the Algerian (63%) and the Moroccan basin parts (55%). Small reservoirs and hillside reservoirs are quantitatively important in the interception of these sediments compared to large reservoirs. If we only considered the dams included in the widely used Global Reservoir and Dam (GRanD) database which comprises mainly large reservoirs sediment retention behind dams would account for 36% of the natural suspended particulate matter (SPM) flux to the Mediterranean Sea. Our data reveal negative correlation between sediment retention and natural erosion rates among the three Maghreb countries, which can be explained by the greater difficulties to build dams in steep terrains where natural sediment yields are high. Although the lowest sediment retention rates are found in the Moroccan part of the MMB, it is probably here where riverine sediment starvation has the greatest impacts on coastline dynamics. Understanding the impact of dams and related water infrastructures on riverine sediment dynamics is key in arid zones such as the MMB, where global warming is predicted to cause important changes in the climatic conditions and the water availability.
Les effets économiques de l'épidémie du SIDA en Afrique subsaharienne : une analyse d'équilibre général
Authors: Kambou Gérard , Devarajan Shantayanan , Over A.Mead
Published: July 2018

Depuis son apparition au début des années 80, le Syndrome d'immuno-déficience acquise (sida) est devenu une épidémie mondiale qui se propage rapidement, bien qu'à des degrés divers, à travers continents, pays, groupes d'âge et classes socio-économiques. Les économistes et les hommes politiques sont préoccupés non seulement par les moyens d'atténuer la douleur, la rupture sociale et la souffrance humaine qu'il inflige à son passage, mais également par les conséquences économiques significatives des maladies causées par le sida. De quelle manière la propagation du virus et l'augmentation de la mortalité adulte qui en résulte affecteront-elles la performance économique d'un pays ? Les dépenses pour le traitement du sida absorberont-elles une part importante et croissante de l'épargne nationale faisant ainsi obstacle à la formation du capital et à la croissance économique ? Ces questions, qui sont liées, sont d'une importance considérable pour les responsables de la prise des décisions dans des pays où les ressources humaines et financières sont particulièrement rares.
Les difficultés de la mesure du taux de change réel : l'exemple du Sénégal
Authors: Guillaumont Jeanneney Sylviane
Published: July 2018

Dans les années quatre-vingt la politique d'ajustement structurel dans les pays en développement a toujours eu pour objectif de modifier le «taux de change réel» conçu comme le prix relatif des biens échangeables et non échangeables internationalement. Comme ce prix n'est pas directement mesurable, il est généralement approché par le «taux de change effectif réel» ou moyenne des indices du cours du change du pays concerné vis-à-vis de ses partenaires commerciaux, corrigés par l'évolution relative des prix dans le pays et à l'étranger. L'article montre que l'assimilation des deux concepts risque d'entraîner des conclusions erronées quant à l'efficacité de la politique d'ajustement lorsque, ce qui est souvent le cas, le pays a simultanément modifié sa politique de contrôle des prix intérieurs et sa politique commerciale extérieure. Il s'appuie sur l'exemple du Sénégal où l'enjeu du débat est d'autant plus important que ce pays a tenté d'ajuster sa balance des paiements sans dévaluer sa monnaie.
L'intégration économique : un nouvel enjeu pour la zone franc
Authors: Guillaumont Patrick , Guillaumont Jeanneney Sylviane
Published: July 2018

The recent studies about economic integration have underlined that during the eighties the main regional agreements aimed at importing institutions or credibility in economic policy more than at increasing intrazone trade. Franc Zone African Countries have had an institutional cooperation for more than thirties years and have developed this cooperation during the recent years. In the light of this experience, the present paper shows the issues at state and the limits of this new form of integration. It also studies why in Africa the institutional cooperation may be prerequisite of trade integration.
Pour une politique de la qualité de l'école primaire en Afrique. Evaluation des acquis des élèves en CP et en CM au Togo
Authors: Jarousse Jean-Pierre , Mingat Alain
Published: July 2018

La préparation des choix de politique éducative, en particulier dans les pays d'Afrique qui font face à des contraintes démographiques et économiques très fortes, ne peut se faire de manière totalement intuitive. Elle suppose, d'une part, une mesure de l'influence des différents facteurs de la production scolaire sur la qualité de cette dernière et, d'autre part, une évaluation complémentaire des coûts de mise en œuvre de ces différents facteurs. Cet article, qui fait référence à l'enseignement primaire togolais, se limite à la première de ces deux étapes et propose un examen de l'impact des différents modes d'organisation scolaire sur les apprentissages des élèves de CP et de CM. Les résultats obtenus offrent déjà des orientations utiles en matière de politiques éducatives en montrant que les programmes les plus fréquemment mis en œuvre (construction scolaire «en dur», recrutement d'enseignants bacheliers), et qui comptent parmi les plus coûteux, n'ont qu'un impact très limité sur la qualité des apprentissages.
La libéralisation du commerce au Mali : une analyse du jumelage entre achats domestiques et attribution des licences d'importation
Authors: E. Takacs Wendy
Published: July 2018

Le Mali a imposé, pour un certain nombre de produits, un système de licences d'importation qui oblige les importateurs à acheter une quantité donnée de produits maliens pour obtenir une licence d'importation. Ce système a le même effet qu'un droit de douane dont le produit serait transféré à l'industrie domestique sous forme de subvention. Le coût de ce jumelage est parfois supérieur, parfois inférieur, au coût d'un droit de douane, selon l'objectif de la politique économique et selon la structure de la branche d'activité protégée. Si, de plus, le prix des produits considérés est réglementé, la séquence suivie pour supprimer le contrôle des prix devient un élément important.
Les apports de la théorie des choix publics à l'analyse des problèmes de développement
Authors: Lafay Jean-Dominique
Published: July 2018

L'article examine dans quelle mesure la théorie des choix publics peut répondre aux besoins analytiques actuels de l'économie du développement. La section I montre que cette théorie est méthodologiquement intéressante : 1 ) pour son étude du comportement des agents politiques et administratifs ; 2) pour la façon dont elle permet de greffer un système politique simplifié sur le système économique. La section II passe en revue les principales applications, effectives ou potentielles, des divers outils analytiques aux problèmes de développement (théories du comportement étatique, de la bureaucratie, des groupes d'intérêt, de recherche de rente, etc.). La section III présente un cas concret de modèle politico-économique appliqué aux problèmes d'ajustement dans les PVD.
Chocs et ajustement de la balance des paiements : la «méthode Balassa» révisée et appliquée au Sénégal
Authors: Montalieu Thierry , Plane Patrick
Published: July 2018

L'article propose quelques aménagements à la méthodologie employée par Balassa (1981) pour analyser l'impact des chocs extérieurs sur la balance commerciale des pays importateurs de pétrole et les réactions de politique économique adoptées pour y faire face. Dans le cadre révisé nous reportons la réflexion sur les variations du compte courant par rapport à une situation de référence glissante. Des équations économétriques sont estimées pour corriger les variations en volume des importations et des exportations de l'action de facteurs exogènes. Elles permettent de mieux saisir le rôle respectif de la substitution à l'importation et de la promotion des exportations. L'application au cas du Sénégal met en lumière les caractéristiques d'évolution de l'ajustement structurel sur la période 1972-1990.
Préserver la zone CFA : la coordination macro-économique après la dévaluation
Authors: Devarajan Shantayanan , Walton Michael
Published: July 2018

The recent 50 percent devaluation of the CFA Franc reinforces the importance of macro-economic coordination in the two monetary unions. The existing rule-based arrangements, such as the limit of a country's central-bank borowing being 20 percent of fiscal receipts, have not prevented some fiscal laxity, with the costs of one member's excesses potentially spilling over to the union as a whole. If the benefits of membership in the cfa zone (monetary discipline, low inflation) are to be preserved, the existing arrangements will need to be modified. The paper proposes that the 20 percent rule be strengthened to include a limit on each country's fiscal deficit and debt ; that sanctions on errant states be imposed through reduced access to borrowing ; and that the central banks finance quasi-fiscal deficits through the countries' budgets.
L'unification des marchés des changes dans les pays en développement
Authors: Agenor Pierre-Richard
Published: July 2018

Parallel markets for foreign exchange exist in most developing countries. The first part of the paper presents an overview of the main characteristics of these markets. The second part examines the short-and long-run effects of policies aimed at unifying the official and parallel currency markets. A simple model with rational expectations is developed to examine short-term movements in prices and net foreign assets. Longer-run inflationary effects are discussed by introducing the government budget constraint. The analysis shows the importance of a close coordination of monetary and fiscal policies to ensure the success of this type of reform.
L'Inde et la Chine : développement économique et bien-être social
Authors: Drèze Jean
Published: July 2018

The paper compares India's and China's economic and social performances. The analysis relies on recent results and puts them in an historical perspective. The author underlines Chinese progress in the area of health, education, social security... ; the lessons of Chinese experience could be useful to Indian reforms.
Politique commerciale et migration internationale à court et moyen terme
Authors: Schiff Maurice W.
Published: July 2018

The traditional trade literature assumes that trade liberalization reduces international factor price differences and results in lower migration, with trade and migration being substitutes. The assumptions made in that literature do not necessarily reflect South-North conditions. On the other hand, the migration literature claims that trade and migration are complements, so that freeing trade raises migration, at least in the short run. The arguments made in that literature better reflect South-North conditions but have lacked a rigorous basis.

In this paper, the author presents three scenarios and related models to explain the complementarity between migration and trade in a South-North context. The first one incorporates migration costs as a constraint, the second one considers factor specificity, and the third one examines the fact that the most protected sectors in a number of reforming ldcs are labor intensive. The results, especially those of the first scenario, suggest that the impact of nafta may very well be to increase migration rather than to reduce it.
La Chine et la convergence
Authors: Guillaumont Patrick , Boyreau-Debray Geneviève
Published: July 2018

This paper considers how specific the Chinese growth experience is in the convergence debate. It shows the location of China within the cross-country relations of (absolute and conditional) convergence and its move since the transition period. Then it evidences a cross-province relation of convergence within China, stronger if this is conditional than absolute. Some conclusions are drawn related to the place of Chinese growth in world growth.
Transition économique et réforme de la politique commerciale en Chine
Authors: Fukasaku Kiichiro , Solignac Lecomte Henri-Bernard
Published: July 2018

Trade policy reform is an essential feature of China's economic transition to a market economy. On the one hand, the liberalisation et decentralisation of export activities has boosted exports. On the other hand, the reform of China's import regime has been progressing much more slowly. This has two negative consequences. The persisting combination of high nominal protection rates and numerous tariff exemptions creates a dual regime : export-oriented firms enjoy free access to imports, while the domestic sector remains highly protected from international competition, which allows for continuing misallocation of resources. This incompleteness of trade reforms currently prevents China from joining the wto, which might eventually hamper its further integration into the world economy.
Les déterminants du commerce extérieur de la Chine
Authors: Hua Ping
Published: July 2018

The sensibility of China's foreign trade to relative prices in short and long terms has been confirmed for 1978-1994 period, using the techniques of cointegration and error-correction representation. This sensibility has been stronger for manufactured products. The long-run revenue-elasticity of imports is considerably smaller than in the short-run because of import substitution policy. The model of foreign exchange allocation, which uses the foreign exchange receipts and reserves as independent variables, has explained the volume of China's foreign trade. These variables are however only appropriate in short run when they have been introduced in traditional function. Economic activities have influenced positively the supply of exports.
Le secteur informel urbain et l'ajustement au Cameroun
Authors: Cogneau Denis , Razafindrakoto Mireille , Roubaud François
Published: July 2018

Cet article présente une analyse de la place du secteur informel urbain dans la dynamique des économies africaines. Des données d'enquêtes originales menées au Cameroun fournissent une série de faits stylisés portant sur les caractéristiques principales de l'offre et de la demande de produits informels et sur l'évolution du marché du travail urbain en période d'ajustement structurel. Une étude en équilibre partiel d'une petite économie urbaine amène à la formulation d'une typologie théorique des activités informelles, fondée sur l'hétérogénéité des qualifications et de la qualité des produits. Cette typologie est ensuite évaluée dans le cadre d'un modèle d'équilibre général appliqué, sur la base d'une simulation de l'ajustement budgétaire et monétaire qui a été mis en œuvre entre 1993 et 1995. La production et l'emploi du secteur informel camerounais sont sans ambiguïté contra-cycliques, tandis que le revenu réel par tête se révèle assez peu sensible à la conjoncture des revenus publics et formels.
L'intégration monétaire avant l'intégration commerciale : le cas de l'Afrique de l'Ouest
Authors: Laporte Bertrand
Published: July 2018

Regional integration schemes have experienced a big surge in the world over the past thirty years. Contrary to the usual process, uemoa countries have led a «monetary agreement first, trade agreement after» strategy. These countries have the most important intra-regional trade in West Africa. Monetary agreement reduces real exchange rate instability and prevents rough and repeated monetary adjustments. The stabilisation of macro-economic environment is hence the main condition to the expansion of intra-regional trade. Trade agreement can then take place without creating regional desequilibrium. This paper uses a bilateral trade gravity model for west african countries to show that a «monetary agreement first, trade agreement after» strategy, could be a better way to achieve regional integration between developing countries.
Structure de propriété et comportement d'investissement en environnement incertain : estimations sur données de panel du secteur manufacturier camerounais
Authors: Zeufack Albert G.
Published: July 2018

Ownership structure and investment behaviour facing uncertainty : estimations on panel data of the cameroonian manufacturing sector

This paper analyses investment behaviour of private firms facing high demand uncertainty. The econometric estimation of a stochastic model on panel data of 68 firms of the cameroonian manufacturing sector during the adjustment period suggests that uncertainty has negatively affected their investment decisions. Moreover, the estimation do not reject the hypothesis that a firm's reaction to uncertainty might depend on its ownership structure. Foreign private investors might be more sensitive to demand uncertainty than their domestic counterparts.
Prêt de groupe, aléa moral et création d'une garantie sociale
Authors: Conning Jonathan
Published: July 2018

Group Lending, Moral Hazard, and the Creation of Social Collateral

This paper studies joint liability loan contracts such as those used by the Grameen Bank of Bangladesh. Group lending is modeled as a multi-task principal-multiagent problem in which each borrower in a borrowing group is given incentives to choose unobserved actions both as an entrepreneur on their own production project, and as a monitor of other borrowers. The analysis shows that «social collateral» to replace missing physical collateral can be created in certain circumstances, but that group loans will be offered by lenders and chosen by borrowers ahead of other forms of finance only where group members have a very substantial monitoring and enforcement advantage relative to outside monitoring intermediaries and the correlation in project returns across borrowers is not too large. Additional results concerning group formation, collusion amongst borrowers, and the cost and benefits of group loans versus other forms of finance available on the same market are discussed.
De l'efficacité allocative des contrats agricoles : Cheung avait-il raison ?
Authors: Ai Chunrong , Arcand Jean-Louis , Ethier François
Published: July 2018

En présence de risque moral, la théorie des contrats prédit que le métayage sera assujetti au problème de l'inefficacité marshallienne, ce qui veut dire que les métayers utiliseront des quantités d'intrants différents sur les terres qu'ils exploitent par opposition aux propriétaires-exploitants. Dans ce papier, nous examinons cette question à l'aide d'une base de données unique en son genre collectée en 1993 dans le village tunisien d'EI Oulja, grâce au financement du programme PARADI. Nous appliquons des méthodes économétriques en panel avec effets spécifiques aux ménages qui montrent que les termes des contrats de métayage ont un effet statistiquement significatif sur l'utilisation des intrants et de l'output. Un test direct montre également que le coût d'opportunité de la supervision de la part des propriétaires est non nul. Pour le cas d'EI Oulja, au moins, Cheung n'a pas raison.
La cohésion sociale est-elle un facteur de l'efficience technique des exploitations agricoles en économie de subsistance ?
Authors: Audibert Martine
Published: July 2018

Le modèle de frontière de production stochastique à effets de l'efficience incorporés est utilisé pour étudier l'efficience technique des exploitations agricoles dans une zone de cultures de subsistance au Mali. Les résultats confirment les deux principales hypothèses émises. L'environnement familial et social, d'une part, et l'environnement écologique lorsqu'il est néfaste à l'état de santé de la population, d'autre part, sont des facteurs de l'efficience technique. La mise en évidence de ces effets s'avère primordiale pour la redéfinition des stratégies de développement agricole en Afrique.
L'investissement direct à l'étranger contribue-t-il à la diffusion technologique vers les pays en développement ?
Authors: Grether Jean-Marie
Published: July 2018

Does Foreign Direct Investment Induce Technological Diffusion in Developing Countries ?

This paper develops a Cournot duopoly in which a domestic firm competes with a technologically more advanced foreign-owned firm on the home market. Free technological spillovers are ruled out, but the domestic firm has the option to invest in costly learning activities and catch-up. In this framework, it turns out that technological transfer from a multinational corporation to its foreign affiliate may act against technological diffusion to the domestic firm, particularly if the initial technological gap is wide and the absorption capacity is weak. In line with the infant-industry argument, if such an outcome prevails, discriminatory measures towards FDI (or imports) could help to promote technological diffusion.
Instabilité du prix mondial des céréales et importations des pays en développement : un système de gestion des risques fondé sur le marché
Authors: Sarris Alexander H.
Published: July 2018

World Cereal Price Instability and a Market Based Scheme for Managing the Risk of Developing Country Cereal Imports

The paper first argues that the world cereal markets do not appear to have become more unstable despite recent liberalization and declines in world stocks. Second, the low income food deficit countries (PFRDA) can, by restructuring domestic production, go a long way towards minimising their risk exposure in international markets. Developed countries can provide technical assistance towards that end. Third, there are probably too many resources devoted in pfrdas by households to self-insurance, given the lack of publicly provided insurance schemes. This has the tendency to lower growth. The pfrdas would probably benefit from internationally provided insurance. The paper proposes the insti¬ tution of a fund aimed at providing option like contracts to the PFRDAs, to insure that they would not incur excessive food import costs in times of need. The premiums of such contract could be subsidised by developed countries, as part of their overall aid. While such a fund would not provide full insurance against excessive food import bills, it would go part of the way toward such a goal. The cost to developed and developing countries alike would seem to be smaller than the cost of current arrangements, and the benefits would seem larger.
Les effets économiques de l'intégration au sein de la Communauté économique et monétaire de l'Afrique centrale : estimations en équilibre général pour le Cameroun
Authors: Bakoup Ferdinand , Tarr David G.
Published: July 2018

The Economie Effects of Integration in the Central African Economic and Monetary Community : Some General Equilibrium Estimates for Cameroon

In this paper we quantitatively assess the impact of the cemac on its largest member : Cameroon. We find that Cameroon will gain between 0.41 and 0.62 percent of its GDP. Our decomposition shows that the part of the agreement that calls for further preferential reduction of tariffs is immiserizing, although given the low level of intra-regional imports, the quantitative impact is quite small. Improved access to partner country markets accounts for about one-quarter of the gains. We find, however, that about three-quarters of the gains come from reduction of Cameroon's tariff against the rest of the world. Moreover, our estimates for Cameroon's unilateral trade liberalization show that it can gain marginally even more from full unilateral trade liberalization than it can from implementation of the CEMAC arrangements. Our results incorporate, in an otherwise small open economy model, the fact that Cameroon may possess regional market power, and we assess the difference in results with models with no regional market power.
Taux de change réel, industrialisation rurale et biais urbain en Chine
Authors: Guillaumont Jeanneney Sylviane , Hua Ping
Published: July 2018

La relation entre le taux de change réel et l'inégalité des revenus entre la ville et la campagne est étudiée pour la Chine entre 1978 et 1996. Contrairement à ce qui est habituellement attendu, le modèle théorique prédit que la dépréciation réelle de la monnaie a contribué à accroître le biais urbain, mais que cet effet a pu être tempéré, voire inversé dans les provinces côtières, à cause du développement de l'industrie rurale. L'analyse économétrique confirme ces résultats.
Contrats agricoles en économie du développement : une revue critique des théories et des tests empiriques
Authors: Dubois Pierre
Published: July 2018

Cette revue de la littérature sur les contrats agricoles dans les pays en développement met en évidence les hypothèses et les limites des modèles théoriques utilisés, ainsi que la relative faiblesse des questions empiriques abordées. Les critiques exposées soulignent les difficultés des recherches mais aussi montrent quelques voies peu ou pas explorées qu'il semble pertinent d'étudier. Parmi les approches théoriques, nous montrons l'importance des hypothèses concernant les asymétries d'information, les préférences vis-à-vis du risque, les coûts de transaction, le cadre statique ou dynamique du modèle, la multiplicité des tâches, le type de délégation, la complétude des contrats et les contraintes institutionnelles (contrats linéaires, contraintes financières, responsabilité limitée, contrats liés sur divers marchés...). Pour ce qui est des études empiriques nombreuses, nous résumons les principales questions auxquelles elles tentent de répondre et exposons les limites des méthodes employées. Cette revue permet aussi de formuler de nombreuses directions de recherches jusqu'ici peu abordées.
Banques commerciales et crédit traditionnel dans les pays en développement : efficacité informationnelle et perspectives de croissance
Authors: Tressel Thierry
Published: July 2018

Nous nous intéressons à l'émergence de banques commerciales modernes dans une économie en développement. Les prêteurs dans le secteur informel disposent d'un avantage informationnel par rapport aux banques qui prêtent contre garanties. Néanmoins, les banques agrègent l'information et ainsi sont en mesure d'inférer, de façon endogène, l'état de la nature. L'allocation du capital par les banques est donc potentiellement plus efficace. Nous analysons la période de transition au cours de laquelle le système bancaire se développe.
THE MEDIATING ROLE OF EMPLOYEE JOB PERFORMANCE IN THE IMPACT OF OPEN BOOK MANAGEMENT DIMENSIONS ON CUSTOMER SATISFACTION
Authors: Abdulkarim Alkhamis Faisal
Published: July 2018

This study aimed at investigating the impact of open book management (OBM) on customer satisfaction in the presence of employee job performance as a mediating variable. OBM was measured using employee empowerment, information sharing, employee training, and employee participation in organizational success. A sample consisted of 500 managers and employees from 10 industrial companies in Qassim region were participated in the study. Data were gathered using a questionnaire administered to participants. The final number of questionnaires received was 387 questionnaires with a response rate of 77.4 percent. The results showed positive as well as significant effects of employee training, empowerment and participation on employee job satisfaction and customer satisfaction. The results further pointed out that employee job performance mediated the effect of open book management dimensions on customer satisfaction. The originality of this study wells up from its contribution to literature as it underlined that employee training in the context of open book management should take the first priority, followed by employee empowerment as empowerment efforts do not bear its desired fruits in the absence of an employee who is able to properly implement what he or she empowered to do. It was recommended on the ground of these results to consider employee training, then employee empowerment in the context of OBM. An adoption of OBM is required to keep tabs on employee job performance in order to ensure an effective practice of OBM.
ANALYZING THE FACTORS INFLUENCING TRUST IN A CONSTRUCTION PROJECT: EVIDENCE FROM A SINO-GERMAN ECO-PARK IN CHINA
Authors: Wang Dedong , Li Kaili , Fang Shaoze
Published: July 2018

Trust is regarded as a critical feature and a central mechanism in business transactions, especially in the Chinese guanxi network. In this context, the major objective of this research is to explore the key factors influencing trust in different stages of a construction project from the perspectives of owners and consultants involved in a Sino-German eco-park in China. The analytic network process (ANP) was employed to assess which factors are most closely related to trust and to establish four models to meet the objective of this study. According to the ANP results, trust is strongly influenced by factors that are associated with the mutual interests between owners and consultants. In addition, there are certain differences in the priority of the factors influencing initial trust between owners and consultants, but these gaps gradually decrease over time. The weight of guanxi also decreases over time, and the owners’ and consultants’ guanxi transforms from out-group to in-group focused.
High-contrast Polarimetry Observation of the T Tau Circumstellar Environment
Authors: Yang Yi , Mayama Satoshi , Hayashi Saeko S. , Hashimoto Jun , Rafikov Roman , Akiyama Eiji , Currie Thayne , Janson Markus , Momose Munetake , Nakagawa Takao , Oh Daehyeon , Kudo Tomoyuki , Kusakabe Nobuhiko , Abe Lyu , Brandner Wolfgang , Brandt Timothy D. , Carson Joseph C. , Egner Sebastian , Feldt Markus , Goto Miwa , Grady Carol A. , Guyon Olivier , Hayano Yutaka , Hayashi Masahiko , Henning Thomas , Hodapp Klaus W. , Ishii Miki , Iye Masanori , Kandori Ryo , Knapp Gillian R. , Kwon Jungmi , Kuzuhara Masayuki , Matsuo Taro , Mcelwain Michael W. , Miyama Shoken , Morino Jun-Ichi , Moro-martin Amaya , Nishimura Tetsuo , Pyo Tae-Soo , Serabyn Eugene , Suenaga Takuya , Suto Hiroshi , Suzuki Ryuji , Takahashi Yasuhiro H. , Takami Michihiro , Takato Naruhisa , Terada Hiroshi , Thalmann Christian , Turner Edwin L. , Watanabe Makoto , Wisniewski John , Yamada Toru , Takami Hideki , Usuda Tomonori , Tamura Motohide
Published: July 2018

We conducted high-contrast polarimetry observations of T Tau in the H-band, using the High Contrast Instrument for the Subaru Next Generation Adaptive Optics instrument mounted on the Subaru Telescope, revealing structures as near as 0.″1 from the stars T Tau N and T Tau S. The whole T Tau system is found to be surrounded by nebula-like envelopes, and several outflow-related structures are detected in these envelopes. We analyzed the detailed polarization patterns of the circumstellar structures near each component of this triple young star system and determined constraints on the circumstellar disks and outflow structures. We suggest that the nearly face-on circumstellar disk of T Tau N is no larger than 0.″8, or 117 au, in the northwest, based on the existence of a hole in this direction, and no larger than 0.″27, or 40 au, in the south. A new structure, “N5,” extends to about 0.″42, or 59 au, southwest of the star, and is believed to be part of the disk. We suggest that T Tau S is surrounded by a highly inclined circumbinary disk with a radius of about 0.″3, or 44 au, with a position angle of about 30°, that is misaligned with the orbit of the T Tau S binary. After analyzing the positions and polarization vector patterns of the outflow-related structures, we suggest that T Tau S should trigger the well-known E–W outflow, and is also likely to be responsible for a southwest precessing outflow “coil” and a possible south outflow.
Does Nearby Open Flux Affect the Eruptivity of Solar Active Regions?
Authors: DeRosa Marc L. , Barnes Graham
Published: July 2018

The most energetic solar flares are typically associated with the ejection of a cloud of coronal material into the heliosphere in the form of a coronal mass ejection (CME). However, large flares exist that are not accompanied by a CME. The existence of these noneruptive flares raises the question of whether such flares suffer from a lack of access to nearby open fields in the vicinity above the flare (reconnection) site. In this study, we use a sample of 56 flares from sunspot Cycles 23 and 24 to test whether active regions that produce eruptive X-class flares are preferentially located near coronal magnetic field domains that are open to the heliosphere, as inferred from a potential field source-surface model. The study shows that X-class flares with access to open fields are eruptive at a higher rate than those for which access is lacking. The significance of this result should be moderated due to the small number of noneruptive X-class flares in the sample, based on the associated Bayes factor.