"Taste heterogeneity, labor mobility and economic geography" - A critical reconsideration and correction

This article reconsiders the linear new economic geography model under heterogeneous agents developed by Tabuchi and Thisse (2002) by applying an analytical technique introduced by Ludema and Wooton (1999). Two problematic aspects are identified: first, the divergence pattern for countries which differ in amenities is incorrect. I show that the degree of agglomeration is highest when trade costs are high. Besides this minor problem, the second critical issue concerns the welfare analysis. It is shown in this paper that this model exhibits a latent tendency for overagglomeration when trade costs are high and underagglomeration when trade costs are low, bringing it in line with other welfare analyses of new economic geography models.Agglomeration

When skilled and unskilled labor are mobile: a new economic geography approach

This paper develops an analytically solvable new economic geography model of the ‘footloose entrepreneur’ class in which not only skilled labor is mobile, but also unskilled labor. Allowing unskilled labor to move freely between different regions increases the agglomeration incentive of skilled labor. Depending on the level of unskilled labor mobility, the geographical distribution of economic activity is either a ‘pitchfork’ or a ‘tomahawk’. If unskilled labor is very mobile, complete agglomeration is the only stable outcome. When trade costs are high, skilled and unskilled labor migration reinforce each other leading to agglomeration of both types of labor in the same region. For lower levels of trade cost, unskilled labor returns to its region of origin, whereas skilled labor remains concentrated.agglomeration; migration; economic geography; bifurcation pattern

Differential labor mobility, agglomeration, and skill-biased migration policies

The paper analyzes the impact of skill-biased migration policies under the economics of agglomeration. It therefore develops an agglomeration model with two types of mobile worker who are heterogeneous and differ both within and between skill groups with respect to their migration propensity. On the one hand, the model reveals that the effectiveness of migration policies depends on the level on trade costs. On the other hand, it shows that increasing (reducing) political barriers to migration for one factor of production, reduces (increases) the migration incentive of the other. Consequently, pro-skilled and contra-unskilled migration policies attenuate each other or can even be counterproductive.agglomeration; labor mobility; economic geography; skill-biased migration policies Welfare

Trade and Industrial Policies with Heterogeneous Firms: The Role of Country Asymmetries

This paper explores the role of country asymmetries for trade and industrial policies with heterogeneous firms. Our analysis delivers a number of novel results. First, trade policies, infrastructure policies and industrial policies which improve the business conditions in one country have negative productivity and welfare effects on the trading partner. Second, symmetric trade liberalization is immiserizing for a trading partner whose business conditions are inferior. Third, there are gains from trade even for a country whose monopolistically competitive sector with heterogeneous firms is wiped out by the switch from autarky to trade.firm heterogeneity, welfare, trade policies, industrial policies, business conditions

Trade and Industrial Policies with Heterogeneous Firms: The Role of Country Asymmetries

This paper explores the role of country asymmetries for trade and industrial policies with heterogeneous firms. Our analysis delivers a number of novel results. First, trade policies, infrastructure policies and industrial policies which improve the business conditions in one country have negative productivity and welfare effects on the trading partner. Second, symmetric trade liberalization is immiserizing for a trading partner whose business conditions are inferior. Third, there are gains from trade even for a country whose monopolistically competitive sector with heterogeneous firms is wiped out by the switch from autarky to trade.firm heterogeneity, welfare, trade policies, industrial policies, business conditions

Heterogeneous Firms, Trade, and Economic Policy: Insights from a Simple Two-Sector Model

The robust empirical finding that exporting firms are systematically different from firms that merely serve domestic consumers has inspired the development of a new brand of trade theory, the theory of heterogeneous firms and trade. The establishment of a canonical model due to Melitz (2003) has induced a recent wave of research which explores various policy issues and policy instruments. This paper uses a simple tractable two-sector model of monopolistic competition as unifying framework to bring out key lessons of this recent research. We address the gains from trade, country asymmetries involving technology potentials, market sizes, trade openness and various business conditions as well as the international repercussions that emerge when countries non-cooperatively choose entry subsidies and their levels of basic research. We also reinvestigate the process of market exit.firm heterogeneity, monopolistic competition, economic policies and welfare

The Art of Climate Change

The warnings about global warming and climate change started in 1965 when “President Lyndon B. Johnson’s Scientific Advisory Council cautioned that constant increase in atmospheric carbon dioxide could modify the heat balance of the atmosphere” (Marshall, 2014). In 2014, the Intergovernmental Panel on Climate Change states that “continued emission of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems” (IPCC, 2014). Yet, globally, we have made little progress on addressing this large-scale, human-induced environmental threat. Dr. Renee Lertzman explains that it is “environmental melancholia” (Gregoire, 2016), an unprocessed sense of anxiety that causes powerlessness and paralysis, that is contributing to societal inertia to address this problem. Current climate change strategies are focused at the policy level and do little to address the emotional state surrounding climate change. Visual art presents an opportunity to explore emotions and unconscious thoughts, and allows exploration of feelings surrounding climate change. It also may be a way to humanize climate change in a way that data and science cannot. This project involves participatory design research through individual photography, personal anecdotes and small group image sorting and discussion. It attempts to evoke personal meaning associated with climate change and suggests ways to scale the dialogue. KEYWORDS: climate change, photography, participatory researc

Heterogeneous and rate-dependent streptavidin-biotin unbinding revealed by high-speed force spectroscopy and atomistic simulations

Receptor-ligand interactions are essential for biological function and their binding strength is commonly explained in terms of static lock-and-key models based on molecular complementarity. However, detailed information of the full unbinding pathway is often lacking due, in part, to the static nature of atomic structures and ensemble averaging inherent to bulk biophysics approaches. Here we combine molecular dynamics and high-speed force spectroscopy on the streptavidin-biotin complex to determine the binding strength and unbinding pathways over the widest dynamic range. Experiment and simulation show excellent agreement at overlapping velocities and provided evidence of the unbinding mechanisms. During unbinding, biotin crosses multiple energy barriers and visits various intermediate states far from the binding pocket while streptavidin undergoes transient induced fits, all varying with loading rate. This multistate process slows down the transition to the unbound state and favors rebinding, thus explaining the long lifetime of the complex. We provide an atomistic, dynamic picture of the unbinding process, replacing a simple two-state picture with one that involves many routes to the lock and rate-dependent induced-fit motions for intermediates, which might be relevant for other receptor-ligand bonds.Comment: 21 pages, 4 figure

Evaluating The Long-Term Performance Of Composite Wear Rings In Centrifugal Pumps

Case StudyRefinery instituted a standardization program to install composite wear rings with reduced clearance into a large population of pumps. Purpose of study was to improve pump reliability. Study was conducted on first 61 pumps upgraded. Criteria was pump services < 500 F, refined product, chemical, or utility service (no bottoms or slurries). Details of installation, operating conditions, and preliminary results were published at 2007 International Pump Users Symposium. This Case Study provides long-term results after more than 4 years of running time