International Trade and Income Distribution

This paper applies the inframarginal analysis, which is a combination of marginal and total cost-benefit analysis, to investigate the relationship between division of labor, the extent of the market, productivity, and inequality of income distribution. The model with transaction costs and exogenous and endogenous comparative advantages shows that as transaction conditions are improved, the general equilibrium discontinuously jumps from autarky to partial division of labor with a dual structure, then to the complete division of labor where dual structure disappears. In this process different groups of individuals with different transaction conditions get involved in a certain level of division of labor at different stages of development. As the leading group gets involved in a higher level of division of level, leaving others behind dual structure emerges and inequality increases. As latecomers catch up dual structure disappears and inequality declines. When the leader goes to an even higher level of specialization, dual structure occurs and inequality increases again. Inequality decreases again as the latecomers catch up. Hence, the equilibrium degree of inequality fluctuates in this development process. The relationship between inequality and productivity is neither monotonically positive nor monotonically negative. It might not be of inverted U-curve. The key driving force of economic development and trade is improvement in transaction conditions.Income distribution, division of labor, dual structure, economic development

V-shaped temperature dependences and pressure dependence of elementary reactions of hydroxyl radicals with several organophosphorus compounds

Organophosphorus compounds have brought increasing attention since they are widely used as flame-retardants, which can take effect in combustion via reactions with reactive radicals. These reactions are influenced by variables such as temperature and pressure, resulting in a temperature and pressure dependent rate constant. Studying this reaction kinetics has great importance in both combustion reaction and atmospheric environment. This study is focused on kinetics of several elementary reactions of combustion importance. The kinetics of hydroxyl radicals were studied using pulsed laser photolysis coupled to transient UV-vis absorption spectroscopy over the 295 - 837 K temperature range and the 1 - 30 bar pressure range. Hydroxyl radical was generated by photolysis of N2O/H2O/He. The time-resolved OH absorption profiles were fitted by different models to get the reaction rate constant at corresponding reaction conditions. Three such reactions were experimentally studied, reactions of OH with trimethyl phosphate (TMP), dimethyl methyl phosphonate (DMMP), and trimethyl phosphite (TMPi). All three compounds exhibit the features predicted for elementary reactions with negative (submerged) barriers, where V-shaped temperature dependencies are observed (negative at low and positive at elevated temperatures). For reaction OH + DMMP, bath gas pressure dependence was also observed (1 ? 30 bar, He). These reactions are suggested to have transition states with the ground state lying below the ground state of the reactants, presumably caused by the long-range electrostatic interactions in the transition states

Pattern of Trade and Economic Development in the Model of Monopolistic Competition

The paper introduces differences in production and transaction conditions between countries into the model of monopolistic competition to investigate the interplay between trade policies and development strategies. It applies inframarginal analysis, which is total benefit analysis between corner solutions in addition to marginal analysis of each corner solution, to show that as transaction conditions are improved, the general equilibrium may discontinuously jump across different patterns of trade and economic development. It compares the marginal and inframarginal comparative statics of equilibrium in the model of monopolistic competition with the core theorems in the neoclassical trade models and with conventional wisdom in development economics. It shows that as analytical framework is altered, the meanings of concepts and related empirical observations will be changed too.trade pattern, development strategy, income distribution, terms of trade

Trade Pattern and Economic Development When Endogenous and Exogenous Comparative Advantages Coexist

This paper applies the infra-marginal analysis, which is a combination of marginal and total cost-benefit analysis, to a model with both constant returns and increasing returns in production and with exogenous and endogenous comparative advantages. It demonstrates that as transaction conditions are improved, the general equilibrium discontinuously jumps from autarky to partial division of labor with a dual structure, then to the complete division of labor where dual structure disappears. Two types of dual structure may occur in the transitional stage of economic development and globalization. One of them involves the division of labor in the developed economy and autarky in the less developed economy, generating increasing disparity of per capita real income between the two types of economies. The other involves a domestic dual structure in the less developed economy, where the population is divided between commercialized sector which trades with foreign country and self-sufficient sector which is not involved in trade. All gains from trade go to the developed economy. This paper shows that deterioration of a country's terms of trade may concur with an increase of gains that this country receives from trade provided productivity progress from an expanded network of division of labor outpaces the deterioration of terms of trade. In the model with both endogenous and exogenous comparative advantages, a country may exports a good with exogenous comparative disadvantage if endogenous comparative advantage dominates this exogenous comparative disadvantage

Pattern of Trade and Economic Development in the Model of Monopolistic Competition

The paper introduces differences in production and transaction conditions between countries into the model of monopolistic competition to investigate the interplay between trade policies and development strategies. It applies inframarginal analysis, which is total benefit analysis between corner solutions in addition to marginal analysis of each corner solution, to show that as transaction conditions are improved, the general equilibrium may discontinuously jump across different patterns of trade and economic development. It compares the marginal and inframarginal comparative statics of equilibrium in the model of monopolistic competition with the core theorems in the neoclassical trade models and with conventional wisdom in development economics. It shows that as analytical framework is altered, the meanings of concepts and related empirical observations will be changed too

Investigating the impacts of street environment on pre-owned housing price in Shanghai using street-level images

[EN] Studies considering street environment quality’s impact on housing value were limited to top-down variables such as the green ratio measured from satellite maps. In contrast, this study quantified street views’ impacts on the value of second-hand commodity residential properties in Shanghai based on analysis of street view imagery. (1) It applied computer vision to objectively measure street features from largely accessible street view imagery. (2) Based on the classical urban design measures frameworks, it applied machine learning to evaluate human perceived street quality as street scores systematically, in contrast to the common practice of doing so in a more intuition-based fashion. (3) It further identified important indicators from both human-centered street scores as well as the more objective street feature measures with positive or adverse effects on property values based on a hedonic modeling method. The estimation suggested both street scores and features are significant and nonnegligible. For the perceived street scores (from 0-10 scale), neighborhoods with a unit increase in their “enclosure” or “safety” score enjoy price premium of 0.3% to 0.6%. Meanwhile, streets with 10% greater tree canopy exposure are attributable to a 0.2% increase in the property value. This study enriched our current understanding at a micro level of the factors that impact property values from the perspective of the built environment. It introduced human-centered perception of street scores and objective measures of street features as spatial variables into the analysis of neighborhood attribute vectors.Qiu, W.; Huang, X.; Li, X.; Li, W.; Zhang, Z. (2020). Investigating the impacts of street environment on pre-owned housing price in Shanghai using street-level images. Editorial Universitat Politècnica de València. 29-39. https://doi.org/10.4995/CARMA2020.2020.11410OCS293

A Dual-Stream Neural Network Explains the Functional Segregation of Dorsal and Ventral Visual Pathways in Human Brains

The human visual system uses two parallel pathways for spatial processing and object recognition. In contrast, computer vision systems tend to use a single feedforward pathway, rendering them less robust, adaptive, or efficient than human vision. To bridge this gap, we developed a dual-stream vision model inspired by the human eyes and brain. At the input level, the model samples two complementary visual patterns to mimic how the human eyes use magnocellular and parvocellular retinal ganglion cells to separate retinal inputs to the brain. At the backend, the model processes the separate input patterns through two branches of convolutional neural networks (CNN) to mimic how the human brain uses the dorsal and ventral cortical pathways for parallel visual processing. The first branch (WhereCNN) samples a global view to learn spatial attention and control eye movements. The second branch (WhatCNN) samples a local view to represent the object around the fixation. Over time, the two branches interact recurrently to build a scene representation from moving fixations. We compared this model with the human brains processing the same movie and evaluated their functional alignment by linear transformation. The WhereCNN and WhatCNN branches were found to differentially match the dorsal and ventral pathways of the visual cortex, respectively, primarily due to their different learning objectives. These model-based results lead us to speculate that the distinct responses and representations of the ventral and dorsal streams are more influenced by their distinct goals in visual attention and object recognition than by their specific bias or selectivity in retinal inputs. This dual-stream model takes a further step in brain-inspired computer vision, enabling parallel neural networks to actively explore and understand the visual surroundings

Effect of Gradually Decreasing Photoperiod on Immune Function in Siberian Hamsters

Animals usually use photoperiod as an important environmental cue to time the year. In terms of the winter immunocompetence enhancement hypothesis, animals in the non-tropical zone would actively enhance their immune function to decrease the negative influence of stressors such as low temperature and food shortage in winter. In the present study, we mimicked the transition from summer to winter by decreasing photoperiod gradually and examined the variations of immune repsonses in Siberian hamsters (Phodopus sungorus)  to test this hypothesis. Twenty two female adult hamsters were randomly divided into the control (12h light: 12h dark, Control, n=11) and the gradually decreasing photoperiod group (Experiment, n=11). In the experiment group, day length was decreased from 12 h: 12 h light-dark cycle to 8 h: 16 h light-dark cycle at the pace of half an hour per week. We found that gradually decreasing photoperiod had no effect on body composition (wet carcass mass, subcutaneous, retroperitoneal, mesenteric and total body fat mass) and the masses of the organs detected such as brain, heart, liver and so on in hamsters. Similarly, immunological parameters including immune organs (thymus and spleen), white blood cells and serum bacteria killing capacity indicative of innate immunity were also not influenced by gradually decreasing photoperiod, which did not support the winter immunocompetence enhancement hypothesis. However, gradually decreasing photoperiod increased phytohaemagglutinin response post-24h of PHA challenge, which supported this hypothesis. There was no correlation between cellular, innate immunity and body fat mass, suggesting that body fat was not the reasons of the changes of cellular immunity. In summary, distinct components of immune system respond to gradually decreasing photoperiod differently in Siberian hamsters