AN ALGORITHM FOR THE SPATIAL PRICE EQUILIBRIUM PROBLEM ON A GENERAL NETWORK IN THE SPACE OF THE PATH FLOWS*

ABSTRACT. The spatial price equilibrium on a general network may be formulated as a nonlinear-cost mathematical programming problem with simple constraints, when the decision variables are the path flows. The solution of this problem is difficult due to the very large number of variables (paths) and the impracticality of generating all the paths from all the origins to all the destinations. In this paper, we develop a Gauss-Seidel-Newton Projection algorithm and combine it with a restriction strategy. That makes it unnecessary to generate a priori all the paths. This algorithm may be further improved by exploiting the equivalence between the spatial price equilibrium on a general network and the network equilibrium. Computational results that we present in this paper demonstrate the efficiency of the proposed solution algorithms.     

Reconstructing the history of nationalist cognition and everyday nationhood from personal accounts

New approaches to nationalism have focused on the role of human agency within nation‐building structures (nationhood from below, everyday nationalism, experiences of nation, personal nationalism, etc.). However, the development of specific methodologies is still scarce. This paper proposes the use of personal accounts (mostly journals and autobiographies, but not only) as sources for qualitative historical research in nations and nationalism. Departing from the concepts of ‘identity’, ‘experience’ and ‘memory’, it is argued that, although very problematic, these sources are a valid path to the study of nations as they are: social phenomena of discursive nature and political frame, whose real agents are individuals. When these agents narrate their lives employing the nation as a meaningful category, they are not producing mere second‐hand reflections of superior and prior realms, but are performing microhistorical acts of nation‐making that are significant for understanding any case of nation‐building. The paper includes an empirical example using British personal accounts from the Age of Revolutions (c.1780–1840).     

Beyond Adornment: Cowry Use as Potter's Tool in the First Impressed Wares of the Southwestern Mediterranean Coast (Northern Morocco)

The use of seashells for the decoration of pottery from the sixth millennium cal BC is well known in the western Mediterranean, with the emergence of so-called Cardial Pottery. Actually, the most discussed issue up until now has been the use of bivalves for impressed decoration. However, the experimental approach followed in the present study provides for the first time clear evidence for the utilization of a very specific group of shells as tools for the decoration of some of the early pottery productions in northwest Africa. In particular, we propose the use of cowry, a gastropod family with a well-known ideological and symbolic role in many human cultures around the world. Also, it is suggested that cowry was used for making impressed wares on the opposite European shore. The implications for reconstruction of Neolithic diffusion along both the European and African coasts of the Mediterranean are of great significance.     

WHAT ATTRACTS KNOWLEDGE WORKERS? THE ROLE OF SPACE AND SOCIAL NETWORKS

The aim of this paper is to identify the determinants of the geographical mobility of skilled individuals, such as inventors, across European regions. Among a large number of variables, we focus on the role of social proximity between inventors’ communities. We use a control function approach to address the endogenous nature of networks, and zero‐inflated negative binomial models to accommodate our estimations to the count nature of the dependent variable and the high number of zeros it contains. Our results highlight the importance of physical proximity, job opportunities, social networks, as well as other relational variables in mediating this phenomenon.     

Out-of-Plane Seismic Response of Unreinforced Masonry Walls: Conceptual Discussion,Research Needs,and Modeling Issues

ABSTRACT

Modeling unreinforced masonry walls, subjected to seismic loads applied normal to their plane, has received much attention in the past. Yet, there is a general lack of conformance with regard to what aspects of seismic response a computational model should reflect. Boundary conditions are certainly an important aspect, as the response can involve two-way bending or just one-way bending and, in the second case, along vertical or horizontal directions. In this respect, flexural restraint of wall intersections can be significant in addition to size and placement of openings. Moreover, in-plane damage can modify the boundary conditions and the overall out-of-plane performance. Proper modeling of actions is also relevant, as they can be a result of distortions imposed upon wall elements and/or inertial forces along the span of a wall. Axial forces can markedly affect the out-of-plane response of the wall, particularly vertical compressive forces, which can enhance out-of-plane strength. The outcome of static verifications can be more conservative than that of dynamic analyses, but the latter are much more complex to carry out. These topics are discussed with reference to previous research, observations in the field and in the laboratory, as well as numerical analyses on three-dimensional models.     

Intergroup Dialogue as a Just Dialogue: Challenging and Preventing Normalization in Campus Dialogues

The tensions from the Israeli occupation of Palestine reach around the globe and heated debates over the struggles of these two peoples are evident on U.S. college campuses. The power imbalance represented in the relationship between Palestinians and Israelis is replicated on college campuses. BDS (Boycott, Divestment, and Sanctions) is a response to this inequality, is a movement to end the occupation, and has raised the issue of normalization. Teaching about this conflict presents particular challenges for faculty who negotiate this highly contested issue in classrooms or campus communities, and intergroup dialogue is an important pedagogy that can be used. It is critical to address normalization in intergroup dialogue. We discuss examples and themes of normalization in intergroup dialogue, and present pedagogical and other strategies to prevent and address normalization in intergroup dialogue and in other similar intergroup contact approaches with Arab or Palestinian and Jewish or Israeli participants.