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In this paper, a nonlocal two-component complex modified Korteweg–de Vries (mKdV) equation is investigated and its Darboux transformation is derived. By using the Darboux transformation, soliton solutions are obtained which include dark soliton solution, quasi-W-type soliton, quasi-M-type soliton and periodic solution.

The Sasa-Satsuma equation, a higher-order nonlinear Schr\"{o}dinger equation, is an important integrable equation, which displays the propagation of femtosecond pulses in optical fibers. In this paper, we investigate a generalized Sasa-Satsuma(gSS) equation. The Darboux transformation(DT) for the focusing and defocusing gSS equation is constructed. By using the DT, various of soliton solutions for the generalized Sasa-Satsuma equation are derived, including hump-type, breather-type and periodic soliton. Dynamics properties and asymptotic behavior of these soliton solutions are analyzed. Infinite number conservation laws and conserved quantities for the gSS equation are obtained.

The total first marriage rate (TFMR) of Chinese women shows a downward trend in fluctuations from 1970 to 2016, but it is affected by the tempo distortion caused by changes in the mean age at first marriage. Thus, we compare the total first marriage rate (TFMR) and tempo-adjusted period proportion ever married (PPEM*) to estimate the extent to which the TFMR is affected by tempo effects. We also decompose the women’s TFMR change into its quantum and tempo components from 1970 to 2016 to analyze how much of the changes in TFMR are due to the quantum changes and how much of it is caused by tempo effects. The results show that the tempo effects have had a persistent influence on the period TFMR of Chinese women from 1970 to 2016. The recent decline in the TFMR in Chinese women is mainly due to the first marriage delay, not signaling a retreat from universal marriage.

To understand the groundwater environmental quality and the impact of trace elements in the construction of urban agglomeration in China, this study collected 58 groundwater samples from the core area of the Chang-Zhu-Tan urban agglomeration (Changsha, Zhuzhou, Xiangtan) and quantitatively analyzed the content of 13 dissolved trace element and their spatial distribution characteristics. The health risk assessment model was further used to evaluate the human health risk caused by trace element pollution in groundwater. It was observed that Ba had the highest average concentration (0.28 mg·L−1), whereas Cd had the lowest (2.1 × 10−5 mg·L−1). Compared with China’s groundwater environmental quality standard, the exceeding rates of Se, Mn, Zn, and Ni concentrations were 37.93%, 17.24%, 1.72% and 1.72%, respectively. Ba, Cd, Co, Cr, Cu, Fe, Mo, and Pb did not exceed the corresponding standards. The 13 trace elements were distributed in a scattered pattern in space and the trace elements in both banks of the Xiang River, Zhuzhou, Weishui River and surrounding areas were relatively high. Health risk assessments showed that the carcinogenic risk values of Cd, Cr, and Pb and the health risk values of 10 non-carcinogenic elements were less than the corresponding maximum acceptable risk level. The health risks associated with non-carcinogenic substances through ingestion were higher than those associated with dermal absorption. Among the non-carcinogenic substances, Ba and Mn posed the greatest health risks. With respect to drinking water exposure, Cr had the highest carcinogenic risk, followed by Pb. Furthermore, Cd had the lowest carcinogenic risk. This study recommended that continuous monitoring of Ba, Mn, and Cr in groundwater should be practiced by assessing the risk of these elements in the Chang-Zhu-Tan urban agglomeration.

Background: Japanese quail (Coturnix japonica) are important and widely distributed poultry in China. Researchers continue to pursue genetic selection for heavier quail. The intestinal microbiota plays a substantial role in growth promotion; however, the mechanisms involved in growth promotion remain unclear.Results: We generated 107.3 Gb of cecal microbiome data from ten Japanese quail, providing a series of quail gut microbial gene catalogs (1.25 million genes). We identified a total of 606 main microbial species from 1,033,311 annotated genes distributed among the ten quail. Seventeen microbial species from the genera Anaerobiospirillum, Alistipes, Barnesiella, and Butyricimonas differed significantly in their abundances between the female and male gut microbiotas. Most of the functional gut microbial genes were involved in metabolism, primarily in carbohydrate transport and metabolism, as well as some active carbohydrate-degrading enzymes. We also identified 308 antibiotic-resistance genes (ARGs) from the phyla Bacteroidetes, Firmicutes and Euryarchaeota. Studies of the differential gene functions between sexes indicated that abundances of the gut microbes that produce carbohydrate-active enzymes varied between female and male quail. Bacteroidetes was the predominant ARG-containing phylum in female quail; Euryarchaeota was the predominant ARG-containing phylum in male quail.Conclusion: This article provides the first description of the gene catalog of the cecal bacteria in Japanese quail as well as insights into the bacterial taxa and predictive metagenomic functions between male and female quail to provide a better understanding of the microbial genes in the quail ceca.

Agricultural tillage practices have a significant impact on the generation and consumption of greenhouse gases (GHGs), the primary causes of global warming. Two tillage systems, conventional tillage (CT) and no-tillage (NT), were compared to evaluate their effects on GHG emissions in this study. Averaged from 2018 to 2020, significant decreases of CO

In this paper, we investigate a multi-component AB system that appears in geophysical fluid dynamics. We construct bright–dark soliton solutions of the system using the Hirota’s bilinear method. We obtain asymptotic behaviors of two-soliton solution for the two-component AB system and prove that the interactions between two bright and two dark solitons are elastic. Under various parameter conditions, the oblique interactions and bound states of solitons are analyzed in detail. By use of the Pfaffian technique, we present N -bright and N − dark soliton solutions of the two- and multi-component AB system. The results obtained in this paper can be helpful for the study of vector multi-dark solitons in many physical systems such as nonlinear optics and fluid dynamics.

River ecosystems are under increasing stress in the background of global change and ever-growing anthropogenic impacts in Central Asia. However, available water quality data in this region are insufficient for a reliable assessment of the current status, which come as no surprise that the limited knowledge of regulating processes for further prediction of solute variations hinders the development of sustainable management strategies. Here, we analyzed a dataset of various water quality variables from two sampling campaigns in 2019 in the catchments of two major rivers in Central Asia—the Amu Darya and Syr Darya Rivers. Our results suggested high spatial heterogeneity of salinity and major ion components along the longitudinal directions in both river catchments, pointing to an increasing influence of human activities toward downstream areas. We linked the modeling outputs from the global nutrient model (IMAGE-GNM) to riverine nutrients to elucidate the effect of different natural and anthropogenic sources in dictating the longitudinal variations of the riverine nutrient concentrations (N and P). Diffuse nutrient loadings dominated the export flux into the rivers, whereas leaching and surface runoff constituted the major fractions for N and P, respectively. Discharge of agricultural irrigation water into the rivers was the major cause of the increases in nutrients and salinity. Given that the conditions in Central Asia are highly susceptible to climate change, our findings call for more efforts to establish holistic management of water quality.

Understanding the response of soil respiration to global warming in agro-ecosystem is crucial for simulating terrestrial carbon (C) cycle. We conducted an infrared warming experiment under conventional tillage (CT) and no-tillage (NT) farmland for winter wheat and summer maize rotation system in North China Plain (NCP). Treatments include CT with and without warming (CTW and CTN), NT with and without warming (NTW and NTN). The results indicated that warming had no significant effect on soil moisture in irrigated farmland of NCP (P>0.05). The elevated average soil temperature of 1.1–1.6°C in crop growing periods could increase annual soil CO2 emission by 10.3% in CT filed (P>0.05), but significantly increase it by 12.7% in NT field (P

This study examined the effects of a high-dose Saccharomyces cerevisiae inoculant alone or jointly with Lactobacillus plantarum on nutrient preservation, fermentation quality, and aerobic stability of sweet corn stalk silage. Fresh stalks (231 g dry matter (DM)/kg) were chopped and subjected to the following treatments: (1) deionized water (Uninoculated, U), (2) S. cerevisiae at 1 &times, 108 cfu/g of fresh forage (S), and (3) S. cerevisiae at 1 &times, 108 cfu/g plus L. plantarum at 1 &times, 105 cfu/g (SL). Treated stalks were ensiled in 5-litre laboratory silos for 30, 60, and 90 d. The S and SL silages had a greater (p &lt, 0.001) pH and greater crude protein, ammonia nitrogen/total nitrogen, neutral detergent fibre, acid detergent fibre, and ethanol contents at all three ensiling periods than the U silage. Acetate, propionate and volatile fatty acids in the S and SL silages after 30 and 90 d of ensiling were greater (p &lt, 0.05) than those in the U silage, but they were lower (p &lt, 0.05) in the S and SL silages than in the U silage after 60 d. The lactate and V-score of the S and SL silages were lower (p &lt, 0.001) than those of the U silage at all three ensiling periods. Compared with the U group, the aerobic stability of the S silage after 90 d of ensiling decreased (p &lt, 0.05), and the aerobic stability of the SL silage was unaffected (p &gt, 0.05). Overall, the quality of sweet corn stalk silage was not improved by inoculation with 108 cfu/g of S. cerevisiae alone or in combination with 1 &times, 105 cfu/g of L. plantarum.

In this paper, by employing the Hirota’s bilinear method, we construct the N -soliton solution for an integrable nonlocal discrete focusing nonlinear Schrodinger (dNLS + ) equation, and give the asymptotic analysis of two-soliton solution. The soliton solutions can be reduced to spatial periodic solution or singular solution by choosing the different parameters. Under continuous limit, the discrete soliton yields the one of nonlocal focusing nonlinear Schrodinger equation.

En s’appuyant sur les microdonnées du recensement canadien, cet article analyse les inégalités de revenus entre Canadiens de naissance et immigrants en provenance des pays en développement ainsi que la situation des immigrants sur le marché du travail. Nos résultats montrent clairement qu’il existe une disparité de revenus entre natifs, immigrants occidentaux et non occidentaux, et que cette disparité résulte des caractéristiques qui diffèrent entre ces trois groupes ainsi que de facteurs non observables tels que la discrimination. L’éducation n’a pas le même rendement pour tous les immigrants. La déqualification des immigrants est inégalement distribuée selon leur origine., Based on Canadian census microdata, this paper analyzes income inequality between native-born Canadians and immigrants from developing countries as well as discrimination against immigrants in the labor market. Our results clearly show that there is a disparity in income between the native-born and non-Western immigrants and that this disparity results from differences in characteristics between the three groups and unobservable factors, such as discrimination. Deskilling of immigrants is unequally distributed according to their origin.

The hub-periphery development pattern of the Guangdong economy, to some extent, is a miniature of that of the Chinese economy. The Pearl River Delta, drawing from its first-nature comparative advantages in factor endowments and proximity to Hong Kong SAR, China, and Macau SAR, China, and the second-nature advantages as first-movers in the reforms in attracting and retaining domestic and foreign resources, has developed into a regional economic center. This paper examines the pattern of inter- and intra-provincial migration and that of the concentration of production, to explore the challenges and opportunities for the success of “double transfer.” The paper suggests a four-prong approach, to improve the business environment, support the realization of latent comparative advantages, increase the skill level of the labor force to support the upgrade of the production structure, and protect the vulnerable, to support the inclusive growth of the economy in Guangdong in a sustainable manner.

In this paper, we show that the nonlocal discrete focusing nonlinear Schr\"odinger (NLS) and nonlocal discrete defocusing NLS equation are gauge equivalent to the discrete coupled Heisenberg ferromagnet (HF) equation and the discrete modified coupled HF equation, respectively. Under the continuous limit, the discrete coupled HF equation and the modified discrete coupled HF equation lead to the corresponding coupled HF equation and modified coupled HF equation. This means that the nonlocal focusing and defocusing NLS equations are gauge equivalent to the coupled HF and coupled modified HF equations. The solution of the modified coupled HF equation is obtained by using the solution of nonlocal defocusing NLS equation.

Integrable and nonintegrable discrete nonlinear Schrödinger equations (NLS) are significant models to describe many phenomena in physics. Recently, Ablowitz and Musslimani introduced a class of reverse space, reverse time, and reverse space-time nonlocal integrable equations, including the nonlocal NLS equation, nonlocal sine-Gordon equation, nonlocal Davey-Stewartson equation, etc. Moreover, the integrable nonlocal discrete NLS has been exactly solved by inverse scattering transform. In this paper, we study a nonintegrable discrete nonlocal NLS, which is a direct discrete version of the reverse space nonlocal NLS. By applying discrete Fourier transform and modified Neumann iteration, we present its stationary solutions numerically. The linear stability of the stationary solutions is examined. Finally, we study the Cauchy problem for the nonlocal NLS equation numerically and find some different and new properties on the numerical solutions comparing with the numerical solutions of the Cauchy problem for the NLS equation.

A l'aide des micro-donnees confidentielles des recensements, ce travail examine les facteurs de l'inegalite de revenu et de la pauvrete des immigres au Canada des annees 1990 a 2006. Les resultats montrent que les immigres en provenance des pays en voie de developpement ont ete les plus atteints par les fluctuations economiques. Ils disposent en effet de revenus inferieurs a ceux des Canadiens de naissance et a ceux des immigres venus d'autres pays et, en sus, le rendement de leur capital humain a diminue entre 1991 et 2006. L'importance des flux migratoires venant des pays en voie de developpement a accru l'heterogeneite sociale de la population immigree, aggravant a la fois l'inegalite de revenu entre les immigres du Sud et les autres immigres, et parmi les premiers. Abstract: This paper is based on confidential data from some Censuses and examines the factors of inequality of earnings and of poverty relative to Canadian immigrants during the period of 1990 to 2006. The results of our analysis show that immigrants from developing countries have been the most harmed by economic fluctuations. They have less income than either native-born Canadians or immigrants from other countries; in addition, the return on their human capital has diminished between 1991 and 2006. The importance of migratory flux from developing countries has increased the social heterogeneity of the immigrant population, and has aggravated the inequality of income within the group of immigrants from the South as well as between them and other immigrants.

Nonlinear Schr\"odinger equation, short pulse equation and complex short pulse equation have important application in nonlinear optics. They can be derived from the Maxwell equation. In this paper, we investigate a coupled focusing-defocusing complex short pulse equation. The bright-bright, bright-dark and dark-dark soliton solutions of the coupled focusing-defocusing complex short pulse equation are given. Then the breathers are derived from the dark soliton solution. The rogue wave solutions are also constructed. The dynamics and the asymptotic behavior of the soliton solutions are analyzed, which reveals that there exist the elastic or inelastic collision in bright-bright soliton solution. But the interactions of bright-dark and dark-dark soliton solutions are both elastic., Comment: 26 pages, 16 figures

La question de l’insertion sur le marche du travail urbain des migrants ruraux est aujourd’hui devenue essentielle en Chine. Dans un contexte de reformes economiques, les politiques migratoires en Chine continentale se sont redefinies, intensifiant ainsi fortement les migrations internes. Depuis les annees 1980, cet exode est pour l’essentiel celui des « paysans-ouvriers » (min gong), qui sont ainsi devenus un element majeur de la transition de la Chine vers une economie de marche. Cet article etudie l’insertion de ces migrants ruraux sur le marche du travail de la province du Guangdong a partir d’une base de donnees originale, issues d’une enquete sur les paysans-ouvriers, realisee en 2006. A partir de modeles de duree, nous portons une attention particuliere aux caracteristiques individuelles, temporelles (evolution de la mobilite dans l’emploi au cours du temps) et spatiales (role du lieu d’origine). Nos resultats montrent que les migrants forment un groupe heterogene du point de vue de leurs caracteristiques individuelles et de leur employabilite dans le delta de la riviere des Perles. Les femmes, les jeunes et les peu qualifies sont avantages. La proximite geographique est egalement favorable. Nous examinons enfin les determinants du salaire urbain des paysans-ouvriers qui s’inserent sur un marche du travail de plus en plus segmente et fragmente.

This paper examines the evolution of the size distribution of Chinese cities. Since the relaxation of restrictions on rural—urban migration in the 1980s, China has experienced rapid urban growth. However, cities of different sizes have experienced varying patterns of growth. First, the evolution of city size distribution in China is described by documenting the growth in city size and in the number of existing cities. Then, focusing on the period from 1990 to 2000, the urban evolutionary trend is analysed by means of the Pareto law estimation and the mobility of cities between different size groups is examined with the Markov transition matrix. The convergence hypothesis in the city population growth process is also tested. The results suggest that, contrary to the expected dominance of large city growth, the Chinese city size distribution evened out during the 1990s, with small cities growing more rapidly than large cities.

In this paper, we try to understand the geometry for a nonlocal nonlinear Schrodinger equation (nonlocal NLS) and its discrete version introduced by Ablowitz and Musslimani, Phys. Rev. Lett. 110, 064105 (2013); Phys. Rev. E 90, 042912 (2014). We show that, under the gauge transformations, the nonlocal focusing NLS and the nonlocal defocusing NLS are, respectively, gauge equivalent to a Heisenberg-like equation and a modified Heisenberg-like equation, and their discrete versions are, respectively, gauge equivalent to a discrete Heisenberg-like equation and a discrete modified Heisenberg-like equation. Although the geometry related to the nonlocal NLS and its discrete version is not very clear, from the gauge equivalence, we can see that the properties between the nonlocal NLS and its discrete version and NLS and discrete NLS have significant difference. By constructing the Darboux transformation for discrete nonlocal NLS equations including the cases of focusing and defocusing, we derive their discrete soliton solutions, which differ from the ones obtained by using the inverse scattering transformation.

The flow characteristics of liquids in microtubes driven by a high pressure ranging from 1 MPa to 30 MPa are studied in this paper. The diameter of the microtube is from 3 μm to 10 μm and liquids composed of simple small molecules are chosen as the working fluids. The Reynolds number ranges from 0. 1 to 24. The behavior of isopropanol and carbon tetrachloride under high pressure is found different from the prediction from conventional Hagen-Poiseuille (HP) equation. The normalized friction coefficient C* increases significantly with the pressure. From an analysis of the microtube deformation, liquid compressibility, viscous heating and wall slip, it may be seen that the viscosity at high pressure plays an important role here. An exponential function of viscosity vs pressure is introduced into the HP equation to counteract the difference between experimental and theoretical values. However, this difference is not so marked for di-water.

A random copolymer of propylene with 3.5 mol% ethylene comonomer is firstly fractionated by temperature rising elution fractionation (TREF). Techniques including 13C nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared spectroscopy (FT-IR), gel-permeation chromatography (GPC), crystallization analysis fractionation (Crystaf) and differential scanning calorimetry (DSC) are used to characterize the obtained fraction polymers. The results show that each fraction polymer is composed mainly of isotactic propylene sequence plus a small amount of ethylene comonomer and has uniform molecular weight and ethylene content. The PPP, PPE, and PEP are main part of triad sequence unit. As the elution temperature increasing, ethylene content of the fraction polymers decreases, number average molecular weight increases, and meanwhile number average sequence length of propylene, nP, increases, while that of ethylene, nE, decreases, close to 1. The results show that ethylene content affects linearly the melting temperature (Tm) in a range of ethylene content being as low as less than 10.23 mol%; there is a linear relationship between the reciprocal melting temperature (1000/Tm, K-1) and reciprocal number average molecular weight (Mn-1) in a range of number average molecular weight as low as less than 1.7 × 105.

The enterprise reforms of the 1990s profoundly changed the structure of the economy in China. With the deepening of market economy, the share of the state-owned and collective enterprises declined. Expansion and contraction, as well as establishment and closure, of firms became a common phenomenon. The level and volatility of firm productivity have become increasingly important aspects of the micro performance of the economy. This paper uses a firm-level data set collected annually by the National Bureau of Statistics of China in 1998-2007 to examine the role of different firm characteristics in productivity volatility. The paper measures productivity volatility at the firm level as the standard deviation of the annual growth rate of productivity. The main objectives are twofold: first, it examines the variation of productivity volatility across firms of different characteristics and their evolution over time; second, it investigates the sources of productivity volatility at the firm level in China. The results suggest that in general, productivity volatility at the firm level has declined over time in China. Among firms with different characteristics, large firms, old firms, foreign firms, and firms located in the coastal provinces are less volatile. Firm size and location are the two major factors that drive changes in productivity volatility, one in a positive way and one in a negative way. Although the gaps of volatility between smaller firms and larger firms declined, the gaps between firms located in the coastal provinces and inland provinces increased.

Large numbers of agricultural labor moved from the countryside to cities after the economic reforms in China. Migration and remittances play an important role in transforming the structure of rural household income. This article examines the impact of rural-to-urban migration on rural poverty and inequality in a mountainous area of Hubei province using the data of a 2002 household survey. Since migration income is a potential substitute for farm income, we present counterfactual scenarios of what rural income, poverty, and inequality would have been in the absence of migration. Our results show that, by providing alternatives to households with lower marginal labor productivity in agriculture, migration leads to an increase in rural income. In contrast to many studies that suggest that the increasing share of nonfarm income in total income widens inequality, this article offers support for the hypothesis that migration tends to have egalitarian effects on rural income for three reasons: (1) migration is rational self-selection--farmers with higher expected return in agricultural activities and/or in local nonfarm activities choose to remain in the countryside while those with higher expected return in urban nonfarm sectors migrate; (2) households facing binding constraints of land supply are more likely to migrate; (3) poorer households benefit disproportionately from migration.

This paper examines the growth performance and income inequality in eight Chinese provinces during the period of 1989–2004 using the China Health and Nutrition Survey data. It shows that income grew for all segments of the population, and as a result, poverty incidence has fallen. However, income growth has been uneven, most rapidly in coastal areas, and among the educated. A decomposition analysis based on household income determination suggests that income growth can largely be attributed to the increase in returns to education and to the shift of employment into secondary and tertiary sectors.

Using data from the Survey of Labour and Income Dynamics (SLID) – we analyze non-employment episodes for immigrants from developing countries and compare their situation to that of immigrants from more developed countries and Canadian-born individuals between 1996 and 2006. The methods used allowed us to draw the following conclusion: significant differences exist between these three groups in the labour market mobility, the average duration of a non-employment episode, and the factors that affect the propensity to exit from a non-employment episode. These differences demonstrate a particular disadvantage for immigrants from developing countries. In fact, they tend to spend more time in non-employment episodes compared to their counterparts from the more developed countries and compared to Canadian-born individuals.

In this paper, we propose a new semidiscrete Hirota equation which yields the Hirota equation in the continuum limit. We focus on the topic of how the discrete space step δ affects the simulation for the soliton solution to the Hirota equation. The Darboux transformation and explicit solution for the semidiscrete Hirota equation are constructed. We show that the continuum limit for the semidiscrete Hirota equation, including the Lax pair, the Darboux transformation and the explicit solution, yields the corresponding results for the Hirota equation as δ → 0 .

Using data from the Survey of Labour and Income Dynamics (SLID), we analyze non-employment episodes for immigrants from developing countries, and compare their situation to that of immigrants from developed countries and Canadian-born individuals between 1996 and 2006. The methods used allowed us to draw the following conclusion: significant differences exist between these three groups in labour market mobility, the average duration of a non-employment episode, and the factors that affect the propensity to exit from a nonemployment episode. These differences demonstrate a particular disadvantage for immigrants from developing countries. In fact, they tend to spend more time in non-employment episodes compared to their counterparts from developed countries, and compared to Canadian-born individuals.

Migration and urbanization have transformed the Chinese economy and society in the past 25 years. This paper intends to explore the determinants of population flows and city growth using a panel data at the provincial level in China. The main findings are: (i) regional disparities of urbanization in China, in particular those between coastal and inland areas, are very significant; (ii) the open-door policy has encouraged urban development in China; (iii) the population of small and medium size cities grows faster than that of large cities; (iv) the role of the secondary and tertiary sectors differs from region to region. In central China, the secondary sector actually serves as the push factor for local urbanization; and in coastal region, however, it is the development of the tertiary sector that pushes urbanization; and (iv) the labor force tends to move to cities with good infrastructures.

The main objective of this paper is to study the determinants of city population growth in China during the 1990s', as well as the determinants of migrations towards cities, which constitutes the main source of urban population growth in this period. A second objective is to identify regional differences in the urban growth and migrations, that is, whether urban growth and migration patterns are different between coastal and inland provinces. Additionally, we are interested in the differences between temporary and permanent migrations towards urban areas.

La question de l’insertion sur le marché du travail des immigrants est aujourd’hui devenue essentielle. Les dispositifs mis en place au Canada cherchent à favoriser la réarticulation entre immigration, marché du travail, protection sociale, formation et cohésion sociale. Cet article étudie l’insertion des immigrés sur le marché du travail québécois à quatre points de leur parcours : après 1, 2, 3 et 10 ans de séjour. Outre les caractéristiques individuelles, nous portons une attention particulière à l’impact de l’environnement macroéconomique et des politiques sociales de redistribution sur la probabilité de sortie d’un épisode de non-emploi de ces immigrants. Nos résultats montrent que les immigrés forment un groupe hétérogène du point de vue de leurs caractéristiques individuelles et de leur employabilité. Certains restent marginalisés sur le marché du travail. C’est le cas notamment des femmes, des migrants âgés et dans un premier temps des moins qualifiés. L’assurance chômage et les prestations sociales jouent négativement sur la sortie de l’épisode de non-emploi. Le taux de chômage local exerce un effet significativement négatif sur la probabilité d’avoir un emploi et touche essentiellement l’emploi des immigrants peu qualifiés.

This article examines the migration of rural workers towards the cities in the light of national data on the two periods 1985-1990 and 1990-1995. It briefly considers the restrictions on workers’ mobility, focusing particularly on the main instrument of control, the hukou. The article highlights the finding that despite such continuing obstacles to mobility, the migratory dynamic is consistent with the deepening integration of the Chinese domestic market.

Cet article etudie les migrations des travailleurs ruraux vers les villes en utilisant des donnees nationales sur les deux periodes 1985-1990 et 1990-1995. Il revient brievement sur les restrictions pesant sur la mobilite des travailleurs et notamment sur son principal instrument de controle, le hukou. Ce travail souligne qu’en depit d’entraves persistantes a la mobilite, la dynamique migratoire est coherente avec l’approfondissement de l’integration du marche interieur chinois.

Income inequality in China has risen rapidly in the past decades across regions, between rural and urban sectors, and within provinces. The dynamics of divergence across these sub-national areas have taken the form of a race to the top - meaning that all segments of the population, including the poor with low education in lagging inland rural areas, have experienced gains in average income. The largest gains have been registered by those with higher income and education in leading coastal urban areas. Using the China Economic, Population, Nutrition and Health Survey data of 1989 and 2004, we show that the most important factors explaining overall inequality are differential returns to schooling and sector of employment. A decomposition analysis based on household income determination shows that the increase in returns to education explains two-thirds of income changes in urban areas and one-sixth in rural areas. The widening income gaps are the consequence of higher growth in leading urban and coastal areas and that the skilled population has benefited more from the economic reforms carried out during the last 25 years. The authors argue that rising income inequality can be part of a normal process of development at a certain stage, and that the dynamics of spatial income divergence in the form of "a race to the top" can be desirable to some extent as it unleashes competitive pressure and creates incentives for investment in skills. Continuing to improve market efficiency and investing in people, in particular improving education service in lagging areas to poor people, are important for sustainable growth and equitable distribution in the long run.

Large numbers of agricultural labor moved from the countryside to cities after the economic reforms in China. Migration and remittances play an important role in transforming the structure of rural household income. This paper examines the impact of rural-to-urban migration on rural poverty and inequality in the case of Hubei province using the data of a 2002 household survey. Since remittances are a potential substitute for farm income, the paper presents counterfactual scenarios of what rural income, poverty, and inequality would have been in the absence of migration. The results show that, by providing alternatives to households with lower marginal labor productivity in agriculture, migration leads to an increase in rural income. In contrast to many studies that suggest the increasing share of non-farm income in total income widens inequality, this paper offers support for the hypothesis that migration tends to have egalitarian effects on rural income for three reasons: (i) migration is rational self-selection - farmers with higher agricultural productivities choose to remain in local agricultural production while those with higher expected return in urban non-farm sectors migrate; (ii) poorer households facing binding constraints of land shortage are more likely to migrate; and (iii) the poorest poor benefit disproportionately from remittances.

Nonfarm activity plays an increasingly important role in rural household income. Based on data from the Living Standards Measurement Study in the provinces of Hebei and Liaoning, the authors study the distribution of nonfarm income in rural China. First, they assume nonfarm income as an exogenous transfer to total income to decompose the Gini index. Second, they assume nonfarm income as a potential substitute for farm income to take household choices into account and simulate household income. The results show that nonfarm activity reduces rural income inequality by raising the income of poor households to a larger extent than that of rich households. Improving rural infrastructure and implementing universal basic education are critical to build up the capacity of households (in particular, poor households) to participate in nonfarm activity. Strengthening the links between farm activity and nonfarm activity is essential to optimize the contribution of nonfarm activity to pro-poor rural economic development.

To evaluate the role of transcription factor GATA-3 in the pathogenesis of nasal polyps.The expression of GATA-3 was detected by immunohistochemistry and reverse transcriptase polymerase chain reaction (RT-PCR) in 28 cases of nasal polyps and 17 specimens of normal nasal epithelium. The expression of interleukin-5 (IL-5) in these specimens was detected by enzyme-linked immunosorbent assay (ELISA) meanwhile.Immunohistochemistry showed, as confirmed by RT-PCR, a positive rate of GATA-3 of 89.3% in the nasal polyp (25/28) and 29.4% in the normal nasal mucosa (5/17), P0.05. GATA-3 was mainly distributed in submucous inflammatory cells. The relative density ratio of GATA-3 to GAPDH was 0.618 +/- 0.137 in nasal polyp and 0.21 +/- 0.11 in normal nasal mucosa (P0.05) as indicated by RT-PCR and agarose electrophoresis. The concentrations of IL-5 were 69.4 +/- 15.1 pg/ml and 25.7 +/- 13.0 pg/mg in the two groups respectively. The expression of GATA-3 was positively correlated to the expression of IL-5 in the nasal polyp.Contributing to the overexpression of such cytokines as IL-5, GATA-3 may play an important role in the pathogenesis of nasal polyps.

In this article, by means of using discrete zero curvature representation and constructing opportune time evolution problems, two new discrete integrable lattice hierarchies with n-dependent coefficients are proposed, which related to a new discrete Schr\"{o}dinger nonisospectral operator equation. The relation of the two new lattice hierarchies with the Volterra hierarchy is discussed. It has been shown that one lattice hierarchy is equivalent to the positive Volterra hierarchy with n-dependent coefficients and another lattice hierarchy with isospectral problem is equivalent to the negative Volterra hierarchy. We demonstrate the existence of infinitely many conservation laws for the two lattice hierarchies and give the corresponding conserved densities and the associated fluxes formulaically. Thus their integrability is confirmed., Comment: 14 pages

The main objective of this paper is to evaluate the impact of globalization on internal migrations using data on Chinese provinces. The opening-up policy launched by Chinese authorities at the end of the 1970s, has resulted in widening regional disparities in terms of income and job opportunities that motivated large movements of workers from depressed areas to those offering more prosperous prospects. Our results, based on migrations flows registered on the 1985-2000 period, emphasize that migration choices in China are driven by spatial job opportunity search: differentials of wage and job opportunities prompt redundant workers to engage into migration. Globalization reinforces the capacity of absorption of workers in a given province so that it reduces their incentives to engage into inter-provincial migration. In addition, once workers decide to move outside of their location of origin, they tend to be attracted to outward-oriented provinces. This phenomenon is however weakened by the degree of labor market fragmentation. Alternatively, diversification into a knowledge based economy reinforces the attractive impact of openness for urban migrants.