Trade and Development in a Labor Surplus Economy

This paper looks at a model in which two countries trade agricultural and manufactured commodities. The manufactured-goods sector produces with increasing returns to scale under conditions of monopolistic competition. It is shown that an increase in land endowment (or an increase in agricultural productivity) can have negative welfare implications for both countries. This outcome can result under three different scenarios: asymmetries across countries, i.e. a North-South model, a neoclassical labor market in the home country's instead of a Lewisian market, and alternative utility functions.international trade, labor surplus economy, land expansion, monopolistic competition, North-South model

Trade and Development in a Labor Surplus Economy

This paper looks at a model in which two countries trade agricultural and manufactured commodities. The manufactured-goods sector produces with increasing returns to scale under conditions of monopolistic competition. It is shown that an increase in land endowment (or an increase in agricultural productivity) can have negative welfare implications for both countries. This outcome can result under three different scenarios: asymmetries across countries, i.e. a North-South model, a neoclassical labor market in the home country's instead of a Lewisian market, and alternative utility functions.international trade, labor surplus economy, land expansion, monopolistic competition, North-South model.

Biodiversity and Geography

The paper combines an economic-geography model of agglomeration and periphery with a model of species diversity and looks at optimal policies of biodiversity conservation. The subject of the paper is "natural" biodiversity, which is inevitably impaired by anthropogenic impact. Thus, the economic and the ecological system compete for space and the question arises as to how this conflict should be resolved. The decisive parameters of the model are related to biological diversity (endemism vs. redundancy of species) and the patterns of economic geography (centrifugal and centripetal forces). As regards the choice of environmental-policy instruments, it is shown that Pigouvian taxes do not always establish the optimal allocation.biodiversity, new economic geography, agglomeration, species redundancy vs. endemism, environmental regulation

A thin film model for corotational Jeffreys fluids under strong slip

We derive a thin film model for viscoelastic liquids under strong slip which obey the stress tensor dynamics of corotational Jeffreys fluids.Comment: 3 pages, submitted to Eur. Phys. J.

Biodiversity and Geography

The paper combines an economic-geography model of agglomeration and periphery with a model of species diversity and looks at optimal policies of biodiversity conservation. The subject of the paper is "natural" biodiversity, which is inevitably impaired by anthropogenic impact. Thus, the economic and the ecological system compete for space and the question arises as to how this conflict should be resolved. The decisive parameters of the model are related to biological diversity (endemism vs. redundancy of species) and the patterns of economic geography (centrifugal and centripetal forces). As regards the choice of environmental-policy instruments, it is shown that Pigouvian taxes do not always establish the optimal allocation.biodiversity, new economic geography, agglomeration, species redundancy vs. endemism, environmental regulation

Slip vs viscoelasticity in dewetting thin films

Ultrathin polymer films on non-wettable substrates display dynamic features which have been attributed to either viscoelastic or slip effects. Here we show that in the weak and strong slip regime effects of viscoelastic relaxation are either absent or not distinguishable from slip effects. Strong-slip modifies the fastest unstable mode in a rupturing thin film, which questions the standard approach to reconstruct the effective interface potential from dewetting experiments.Comment: 4 pages, submitted to Eur. Phys. J.

Racial Disparities in Breast Cancer Survival: The Mediating Effects of Macro-Social Context and Social Network Factors

ABSTRACT This study attempts to clarify the associations between macro-social and social network factors and continuing racial disparities in breast cancer survival. The study improves on prior methodologies by using a neighborhood disadvantage measure that assesses both economic and social disadvantage and an ego-network measurement tool that assesses key social network characteristics. Our population-based sample included 786 breast cancer patients (nHWhite=388; nHBlack=398) diagnosed during 2005-2008 in Chicago, IL. The data included census-derived macro-social context, self-reported social network, self-reported demographic and medically abstracted health measures. Mortality data from the National Death Index (NDI) were used to determine 5-year survival. Based on our findings, neighborhood concentrated disadvantage was negatively associated with survival among nHBlack and nHWhite breast cancer patients. In unadjusted models, social network size, network density, practical support, and financial support were positively associated with 5-year survival. However, in adjusted models only practical support was associated with 5-year survival. Our findings suggest that the association between network size and breast cancer survival is sensitive to scaling of the network measure, which helps to explain inconsistencies in past findings. Social networks of nHWhites and nHBlacks differed in size, social support dimensions, network density, and geographic proximity. Among social factors, residence in disadvantaged neighborhoods and unmet practical support explained some of the racial disparity in survival. Differences in late stage diagnosis and comorbidities between nHWhites and nHBlacks also explained some of the racial disparity in survival. Our findings highlight the relevance of social factors, both macro and inter-personal in the racial disparity in breast cancer survival. Findings suggest that reduced survival of nHBlack women is in part due to low social network resources and residence in socially and economically deprived neighborhoods. Our findings indicate that, to improve survival among breast cancer patients, policies need to focus on continued improvement of access to care and reduction of racially patterned social and economic hardship. Additionally, our findings support the need for health care providers to assess social support resources of breast cancer patients at the time of diagnosis

Nucleosynthesis Basics and Applications to Supernovae

This review concentrates on nucleosynthesis processes in general and their applications to massive stars and supernovae. A brief initial introduction is given to the physics in astrophysical plasmas which governs composition changes. We present the basic equations for thermonuclear reaction rates and nuclear reaction networks. The required nuclear physics input for reaction rates is discussed, i.e. cross sections for nuclear reactions, photodisintegrations, electron and positron captures, neutrino captures, inelastic neutrino scattering, and beta-decay half-lives. We examine especially the present state of uncertainties in predicting thermonuclear reaction rates, while the status of experiments is discussed by others in this volume (see M. Wiescher). It follows a brief review of hydrostatic burning stages in stellar evolution before discussing the fate of massive stars, i.e. the nucleosynthesis in type II supernova explosions (SNe II). Except for SNe Ia, which are explained by exploding white dwarfs in binary stellar systems (which will not be discussed here), all other supernova types seem to be linked to the gravitational collapse of massive stars (M$>$8M$_\odot$) at the end of their hydrostatic evolution. SN1987A, the first type II supernova for which the progenitor star was known, is used as an example for nucleosynthesis calculations. Finally, we discuss the production of heavy elements in the r-process up to Th and U and its possible connection to supernovae.Comment: 52 pages, 20 figures, uses cupconf.sty (included); to appear in "Nuclear and Particle Astrophysics", eds. J. Hirsch., D. Page, Cambridge University Pres

Slip-controlled thin film dynamics

In this study, we present a novel method to assess the slip length and the viscosity of thin films of highly viscous Newtonian liquids. We quantitatively analyse dewetting fronts of low molecular weight polystyrene melts on Octadecyl- (OTS) and Dodecyltrichlorosilane (DTS) polymer brushes. Using a thin film (lubrication) model derived in the limit of large slip lengths, we can extract slip length and viscosity. We study polymer films with thicknesses between 50 nm and 230 nm and various temperatures above the glass transition. We find slip lengths from 100 nm up to 1 micron on OTS and between 300 nm and 10 microns on DTS covered silicon wafers. The slip length decreases with temperature. The obtained values for the viscosity are consistent with independent measurements.Comment: 4 figure