Freedom, Servitude and Voluntary Labor

We present an economic framework to revisit and reframe some important debates over the nature of free versus unfree labor and the economic consequences of emancipation. We use a simple general equilibrium model in which labor can be either free or coerced and where land and labor will be exchanged on markets that can be competitive or manipulated or via other non-market collusive arrangements. By working with variants of the same basic model under different assumptions about initial economy-wide factor endowments and asset ownership we can compare equilibrium distributional outcomes under different institutional and contractual arrangements including markets with free labor and free tenancy, slavery, and tenancy arrangements with tied labor-service obligations. Analysis of these different contractual and organizational forms yields insights that accord with common sense, but that are often overlooked or downplayed in academic debates, particularly amongst economists

Network Economics and the Environment: Insights and Perspectives

Local interactions and network structures appear to be a prominent feature of many environmental problems. This paper discusses a wide range of issues and potential areas of application, including the role of relational networks in the pattern of adoption of green technologies, common pool resource problems characterized by a multiplicity of sources, the role of social networks in multi-level environmental governance, infrastructural networks in the access to and use of natural resources such as oil and natural gas, the use of networks to describe the internal structure of inter-country relations in international agreements, and the formation of bilateral "links" in the process of building up an environmental coalition. For each of these areas, we examine why and how network economics would be an effective conceptual and analytical tool, and discuss the main insights that we can foresee

Coupled Tensor Decomposition: a Step Towards Robust Components

Combining information present in multiple datasets is one of the key challenges to fully benefit from the increasing availability of data in a variety of fields. Coupled tensor factorization aims to address this challenge by performing a simultaneous decomposition of different tensors. However, tensor factorization tends to suffer from a lack of robustness as the number of components affects the results to a large extent. In this work, a general framework for coupled tensor factorization is built to extract reliable components. Results from both individual and coupled decompositions are compared and divergence measures are used to adapt the number of components. It results in a joint decomposition method with (i) a variable number of components, (ii) shared and unshared components among tensors and (iii) robust components. Results on simulated data show a better modelling of the sources composing the datasets and an improved evaluation of the number of shared sources

Characterisation of low, medium and high responders following FSH stimulation prior to ultrasound-guided transvaginal oocyte retrieval in cows

In human IVF, the concept of 'low responders' is well known and generally defined as women with poor-response to gonadotrophin stimulation in a previous induction cycle. The objective of this retrospective study is to describe and characterise the concepts of 'low-, medium-, and high-response' and 'low, medium, and high responders' in bovine-assisted reproduction by analysing the OPU-IVF results obtained following 665 gonadotrophin-stimulated sessions conducted in 112 animals, nearly all of which were previously unsuccessful in traditional multiple ovulation and embryo transfer (MOET) programs. They were submitted to OPU and IVP between 1999 and 2003. In reference to these 665 OPU sessions, categories of response were defined based on the overall mean+/-S.D. follicles aspirated and COC obtained i.e., for follicles 14.7+/-9.8 and for COCs 11.7+/-8.1. So arbitrary cut-off values to define the categories of sessions were for follicles 5 and 25, and for COC 4 and 20. The three categories for follicles punctured in one session were therefore follicle low-response (FLR)or=25 follicles and for COCs recovered in one session COC low-response (CLR)or=20 COC. In addition, four categories of animals were also defined: (1) a low responder animal (LRA) had at least one OPU session in which FLR and CLR were observed (genuine low-response, see Section ); these animals did not have any high-response sessions, (2) a medium responder animal (MeRA) had only medium-responses, (3) a high responder animal (HRA) had at least one OPU session in which FHR and CHR were observed; these animals did not have any low-response sessions, and (4) mixed responder animals (MiRA) had both low and high-responses. Finally, we distinguished biological (animals) and technical (recovery rate and ultrasound resolution) causes of response differences. In 'low, high, medium and mixed reponders,' different results were obtained (p<0.05): mean follicle numbers (8.8+/-4.8a, 22.4+/-10.5c, 13.2+/-5.2b,15.1+/-10.2d), COC numbers (6.3+/-3.9a, 18.5+/-8.2c, 10.4+/-4b, 12.0+/-8.3d), embryo numbers (1.8+/-2.1a, 5.6+/-4.9c, 2.5+/-2.7b, 3.5+/-3.8d) and also for recovery rate (72%a, 83%b,79%, 79%) and percentage embryo development (29%, 30%a, 24%b, 29%). In conclusion, the results of this study demonstrate that variability in OPU results has technical (ultrasound resolution and recovery rate) as well as biological (animal) aspects. Selection of animals with extreme (high or low) follicle and COC production results allows us to distinguish three populations: 'low, medium, and high responders' to FSH stimulation