Regional Integration and Dynamic Adjustments: Evidence from a Gross National Product Function for Canada and the United States

We propose an empirical trade model to test for structural change and dynamic effects induced by free trade agreements for the Canadian and US economies. We estimated a translog Gross National Product (GNP) function along with output and factor shares and tested for structural change (abrupt or gradual) which is endogenously determined by the data. After this, we estimated Stolper-Samuelson (SS) and Rybcynski (R) elasticities, and assessed the stability of their sign and magnitude link to the structural change. The null hypothesis of no structural change is soundly rejected for both countries. For Canada, we found gradual structural change that started prior to the implementation of CUSTA and lasted for several years. In the US case, we found evidence of an abrupt structural change occurring in 1995, a year after NAFTA came into force. More interestingly, several SS and R elasticities experienced sign reversals and a magnification effect over the different sub-periods, implying that the categorization of goods in terms of friends or enemies of labour and capital changed during the transition.GNP function; regional integration; structural change; smooth transition regression; dynamic adjustments.

Spatial and temporal variation of malaria entomological parameters at the onset of a hydro-agricultural development in central Côte d'Ivoire

A deeper understanding of the ecology and small-scale heterogeneity of malaria transmission is essential for the design of effective prevention, control and elimination interventions. The spatial and temporal distribution of malaria vectors was investigated in five villages in close proximity to a hydro-agricultural system in Côte d'Ivoire over the course of construction and the early phase of irrigated rice farming.; The study was carried out in five villages (Raffierkro, N'Douakro, Ahougui, Kpokahankro, Koffikro) near Bouaké, central Côte d'Ivoire, between early 2007 and late 2009. In each village, mosquitoes were collected by human landing catches and identified morphologically at genus and species level, and entomological parameters were determined. Plasmodium infection was assessed by dissection and an enzyme-linked immunosorbent assay.; A total of 19,404 mosquitoes belonging to the genus Anopheles were sampled during 328 human-night catches. Before the construction of the hydro-agricultural system, comparable densities of Anopheles gambiae were observed in all villages. In subsequent years, densities in Raffierkro and Ahougui were significantly higher than the other villages [Kruskal-Wallis (KW) test = 31.13, p > 0.001]. The density of Anopheles funestus in the five villages was comparable in the early stage of the project, while a high density was reported in Koffikro at the end (KW test = 11.91, p = 0.018). Transmission of Plasmodium falciparum is perennial in the study area. Over the course of the study, high entomological inoculation rates (EIRs) were found: 219-328 infectious bites per person per year with An. gambiae. For An. funestus considerably lower EIRs were observed (5.7-39.4). Changing patterns of An. gambiae were not correlated with malaria transmission.; In this study setting, located in the bioclimatic transition zone of Côte d'Ivoire, rice cultivation was not observed to increase malaria transmission. The entomological parameters recorded until the onset of rice-growing activities in a hydro-agricultural system presented considerable heterogeneity both in space and time; a strong increase of Anopheles mosquitoes was observed in two of the five villages located in close proximity to the dam and irrigated rice fields. Malaria still is a main public health problem in all villages that require adequate control measures

Towards adaptive topology optimization

This paper presents a new fully-automated adaptation strategy for structural topology optimization (TO) methods. In this work, TO is based on the SIMP method on unstructured tetrahedral meshes. The SIMP density gradient is used to locate solid-void interface and h-adaptation is applied for a better definition of this interface and, at the same time, de-refinement is performed to coarsen the mesh in fully solid and void regions. Since the mesh is no longer uniform after such an adaptation, classical filtering techniques have to be revisited to ensure mesh-independency and checkerboard-free designs. Using this adaptive scheme improves the objective function minimization and leads to a higher resolution in the description of the optimal shape boundary (solid-void interface) at a lower computational cost. This paper combines a 3D implementation of the SIMP method for unstructured tetrahedral meshes with an original mesh adaptation strategy. The approach is validated on several examples to illustrate its effectiveness

Automatic reconstruction of beam structures from 3D topology optimization results

This paper presents a fully-automated reconstruction of beam-like CAD solid structures from 3D topology optimization (TO) results. Raw TO results are first processed to generate a triangulation that represents boundaries of the optimal shape derived. This triangulation is then smoothed and a curve skeletonization procedure is carried out to recover meaningful characteristics of this smoothed triangulation. The resulting skeleton, made with curvilinear geometry, is transformed into straight lines through a normalization process. These straight lines are used to generate a 3D beam structure. Thus, following these steps, a 3D beam structure is automatically derived from TO results. This 3D beam structure is meshed with beam finite elements and since TO non-design material is represented by 3D solid geometry, which is meshed using tetrahedron, the FEA beam structure needs to be rigidly connected with these tetrahedrons. Rigid connections between beam elements and 3D solid elements are ensured using specific FEA beam elements referred to as mini-beams. This results in a mixed-dimensional FEA model with beam and solid finite elements. Results obtained with this mixed-dimensional FEA model allow validating the beam structure obtained from TO results. Performance of the approach is demonstrated on several TO examples

Regional Integration and Dynamic Adjustments: Evidence from a Gross National Product Function for Canada and the United States

We propose an empirical trade model to test for structural change and dynamic effects induced by free trade agreements for the Canadian and US economies. We estimated a translog Gross National Product (GNP) function along with output and factor shares and tested for structural change (abrupt or gradual) which is endogenously determined by the data. After this, we estimated Stolper-Samuelson (SS) and Rybcynski (R) elasticities, and assessed the stability of their sign and magnitude link to the structural change. The null hypothesis of no structural change is soundly rejected for both countries. For Canada, we found gradual structural change that started prior to the implementation of CUSTA and lasted for several years. In the US case, we found evidence of an abrupt structural change occurring in 1995, a year after NAFTA came into force. More interestingly, several SS and R elasticities experienced sign reversals and a magnification effect over the different sub-periods, implying that the categorization of goods in terms of friends or enemies of labour and capital changed during the transition