Structural Characteristics and Evolutionary Drivers of Global Virtual Water Trade Networks: A Stochastic Actor-Oriented Model for 2000-2015.

The globalization of trade has caused tremendous pressure on water resources globally, and a virtual water trade provides a new perspective on global freshwater sharing and water sustainability. No study has yet explored the structural characteristics and drivers of the evolution of global virtual water trade networks from a network structure evolution perspective. This paper aims to fill this critical gap by developing a research framework to explore how endogenous network structures and external factors have influenced the evolution of virtual water trade networks. We constructed virtual water trade networks for 62 countries worldwide from 2000 to 2015 and used an innovative combination of multi-regional input-output data and stochastic actor-oriented models for analytical purposes. Our results support the theoretical hypothesis of ecologically unequal exchange and trade drivers, arguing that virtual water flows from less developed countries to developed countries under global free trade and that unequal trade patterns lead to excessive consumption of virtual water in less developed countries. The results partially support the theoretical content of water endowment and traditional gravity models, finding that trade networks are expanding to farther and larger markets, confirming that national water scarcity levels do not impact the evolution of virtual water trade networks. Finally, we point out that meritocratic links, path dependence, reciprocity, and transmissive links have extreme explanatory power for the evolutionary development of virtual water networks.

Dependência, ciclo do capital e limites do fundo público no Brasil / Dependency, capital cycle and limits of the public fund in Brazil

Resumo: Este artigo visa identificar a participação e os limites do fundo público no ciclo do capital da economia dependente brasileira. Para isso, aborda as implicações do intercâmbio desigual, da transferência de valor e da superexploração da força de trabalho para a composição e direcionamento do fundo público no Brasil, utilizando-se da coleta e análise de dados acerca do sistema tributário brasileiro.

Abstract: This article aims to identify the participation and limits of the public fund in the capital cycle of the Brazilian dependent economy. To this end, it addresses the implications of unequal exchange, value transfer and overexploitation of the labor force for the composition and direction of public fund in Brazil, using the analysis of data about the Brazilian tax system.

Ecologically unequal exchange and disparate death rates attributable to air pollution: A comparative study of 169 countries from 1991 to 2017.

Ambient air pollution is among the most pressing environmental problems in our contemporary world that poses significant risks to global ecological and public health. This study analyzes cross-national heterogeneities in trajectories of death rates attributable to ambient air pollution. Compiling panel data from the Global Burden of Disease (GBD) study, the Direction of Trade Statistics (DOTS), and the World Development Indicators, we create a dataset that tracks 169 countries from 1991 to 2017. Using growth curve models (GCMs), we estimate country-specific trajectories of death rates attributable to air pollution, and condition them on time-invariant and time-varying independent variables. The results suggest that while the global death rate attributable to air pollution has been continuously decreasing, there are heterogeneities in countries' death rate trajectories based on their geographic location and position in the world economy. High-income countries of the global North have perpetually witnessed lower death rates attributable to air pollution compared to middle- and low-income countries of the global South. Moreover, our results indicate that increased export to high-income countries, as a proxy for ecologically unequal exchange, leads to higher death rates from air pollution in middle- and low-income countries.

Ecologically unequal exchange, recessions, and climate change: A longitudinal study.

This study investigates how the ecologically unequal exchange of carbon dioxide emissions varies with economic recessions. I propose a country-specific approach to examine (1) the relationship between carbon dioxide emissions in developing countries and the "vertical flow" of exports to the United States; and (2) the variations of the relationship before, during, and after two recent economic recessions in 2001 and 2008. Using data on 69 developing nations between 2000 and 2010, I estimate time-series cross-sectional regression models with two-way fixed effects. Results suggest that the vertical flow of exports to the United States is positively associated with carbon dioxide emissions in developing countries. The magnitude of this relationship increased in 2001, 2009, and 2010, and decreased in 2008, but remained stable in non-recession periods, suggesting that economic recessions in the United States are associated with variations of ecologically unequal exchange. Results highlight the impacts of U.S. recessions on carbon emissions in developing countries through the structure of international trade.

Rare recombination events generate sequence diversity among balancer chromosomes in Drosophila melanogaster.

Multiply inverted balancer chromosomes that suppress exchange with their homologs are an essential part of the Drosophila melanogaster genetic toolkit. Despite their widespread use, the organization of balancer chromosomes has not been characterized at the molecular level, and the degree of sequence variation among copies of balancer chromosomes is unknown. To map inversion breakpoints and study potential diversity in descendants of a structurally identical balancer chromosome, we sequenced a panel of laboratory stocks containing the most widely used X chromosome balancer, First Multiple 7 (FM7). We mapped the locations of FM7 breakpoints to precise euchromatic coordinates and identified the flanking sequence of breakpoints in heterochromatic regions. Analysis of SNP variation revealed megabase-scale blocks of sequence divergence among currently used FM7 stocks. We present evidence that this divergence arose through rare double-crossover events that replaced a female-sterile allele of the singed gene (sn(X2)) on FM7c with a sequence from balanced chromosomes. We propose that although double-crossover events are rare in individual crosses, many FM7c chromosomes in the Bloomington Drosophila Stock Center have lost sn(X2) by this mechanism on a historical timescale. Finally, we characterize the original allele of the Bar gene (B(1)) that is carried on FM7, and validate the hypothesis that the origin and subsequent reversion of the B(1) duplication are mediated by unequal exchange. Our results reject a simple nonrecombining, clonal mode for the laboratory evolution of balancer chromosomes and have implications for how balancer chromosomes should be used in the design and interpretation of genetic experiments in Drosophila.