Georgi Petrov, 1978 | Landscape painter

Georgi Petrov was born in Dobrich, Bulgaria. He lives and works in Sofia. He holds a Master degree in Art Management from the Academy of Music, Dance and Fine Arts - Plovdiv, Bulgaria. He owns an art gallery in the Dobrich, Bulgaria.

Since 2012 Georgi Petrov is a member of Creative Union of Professional Artist in Russia.

"To me, painting is a heartbeat, love, perception, impetus, state, mood, experience, emption, at times spontaneous, but always created with an open soul… It is born in the interaction between two worlds - the one inside us and the one outside - that establishes another particular reality inspired, however, not always by heroes and happenings which somebody has in…" - Georgi Petrov

More.... Continua......

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Differences in nitrite-oxidizing communities and kinetics in a brackish environment after enrichment at low and high nitrite concentrations

Publication date: Available online 29 October 2015
Source:Journal of Environmental Sciences
Author(s): Wipasanee Tangkitjawisut, Tawan Limpiyakorn, Sorawit Powtongsook, Preeyaporn Pornkulwat, Benjaporn Boonchayaanant Suwannasilp
Nitrite accumulation in shrimp ponds can pose serious adverse effects to shrimp production and the environment. This study aims to develop an effective process for the enrichment of ready-to-use nitrite-oxidizing bacteria (NOB) inocula that would be appropriate for nitrite removal in brackish shrimp ponds. To achieve this objective, the effects of nitrite concentrations on NOB communities and nitrite oxidation kinetics in a brackish environment were investigated. Moving-bed biofilm sequencing batch reactors and continuous moving-bed biofilm reactors were used for the enrichment of NOB at various nitrite concentrations, using sediment from brackish shrimp ponds as seed inoculum. The results from NOB population analysis with quantitative polymerase chain reaction (qPCR) show that only Nitrospira were detected in the sediment from the shrimp ponds. After the enrichment, both Nitrospira and Nitrobacter coexisted in the reactors controlling effluent nitrite at 0.1 and 0.5mg-NO2⁻-N/L. On the other hand, in the reactors controlling effluent nitrite at 3, 20, and 100mg-NO2⁻-N/L, Nitrobacter outcompeted Nitrospira in many orders of magnitude. The half saturation coefficients (Ks) for nitrite oxidation of the enrichments at low nitrite concentrations (0.1 and 0.5mg-NO2⁻-N/L) were in the range of 0.71–0.98mg-NO2⁻-N/L. In contrast, the Ks values of NOB enriched at high nitrite concentrations (3, 20, and 100mg-NO2⁻-N/L) were much higher (8.36–12.20mg-NO2⁻-N/L). The results suggest that the selection of nitrite concentrations for the enrichment of NOB inocula can significantly influence NOB populations and kinetics, which could affect the effectiveness of their applications in brackish shrimp ponds.

Graphical abstract

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Nontargeted identification of peptides and disinfection byproducts in water

Publication date: Available online 29 October 2015
Source:Journal of Environmental Sciences
Author(s): Yanan Tang, Ying Xu, Feng Li, Lindsay Jmaiff, Steve E. Hrudey, Xing-Fang Li
A broad range of organic compounds are known to exist in drinking water sources and serve as precursors of disinfection byproducts (DBPs). Epidemiological findings of an association of increased risk of bladder cancer with the consumption of chlorinated water has resulted in health concerns about DBPs. Peptides are thought to be an important category of DBP precursors in water. However, little is known about actual presence of peptides and their DBPs in drinking water because of their high sample complexity and low concentrations. To address this challenge and identify peptides and non-chlorinated/chlorinated peptide DBPs from large sets of organic compounds in water, we developed a novel high throughput analysis strategy, which integrated multiple solid phase extraction (SPE), high performance liquid chromatography (HPLC) separation, and non-target identification using precursor ion exclusion (PIE) high resolution mass spectrometry (MS). After MS analysis, structures of candidate compounds, particularly peptides, were obtained by searching against the Human Metabolome Database (HMDB). Using this strategy, we have successfully detected 625 peptides (out of 17,205 putative compounds) and 617 peptides (out of 13,297) respectively in source and finished water samples. The source water and finished water samples had 501 peptides and amino acids in common. The remaining 116 peptides and amino acids were unique to the finished water. From a subset of 30 putative compounds for which standards were available, 25 were confirmed using HPLC-MS analysis. By analyzing the peptides identified in source and finished water, we successfully confirmed three disinfection reaction pathways that convert peptides into toxic DBPs.

Graphical abstract

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Budget Rules and Resource Booms and Busts: A Dynamic Stochastic General Equilibrium Analysis

This paper develops a dynamic, stochastic, general-equilibrium model to analyze and derive simple budget rules in the face of volatile public revenue from natural resources in a low-income country like Niger. The simulation results suggest three policy lessons or rules of thumb. When a resource price change is positive and temporary, the best strategy is to save the revenue windfall in a sovereign fund and use the interest income from the fund to raise citizens' consumption over time. This strategy is preferred to investing in public capital domestically, even when private investment benefits from an enhanced public capital stock. Domestic investment raises the prices of domestic goods, leaving less money for government to transfer to households; public investment is not 100 percent effective in raising output. In the presence of a negative temporary resource price change, however, the best strategy is to cut public investment. This strategy dominates other methods, such as trimming government transfers to households, which reduces consumption directly, or borrowing, which incurs an interest premium as debt rises. In the presence of persistent (positive and negative) shocks, the best strategy is a mix of public investment and saving abroad in a balanced regime that provides a natural insurance against both types of price shocks. The combination of interest income from the sovereign fund, transfers to households, and output growth brought about by public investment provides the best protective mechanism to smooth consumption over time in response to changing resource prices.

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Removal of nanoparticles by coagulation

Publication date: Available online 27 October 2015
Source:Journal of Environmental Sciences
Author(s): Aleksandra Popowich, Qi Zhang, X. Chris Le




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Yangtze Three Gorges Reservoir, China: A holistic assessment of organic pollution, mutagenic effects of sediments and genotoxic impacts on fish

Publication date: Available online 26 October 2015
Source:Journal of Environmental Sciences
Author(s): Tilman Floehr, Björn Scholz-Starke, Hongxia Xiao, Josef Koch, Lingling Wu, Junli Hou, Anja Wolf, Axel Bergmann, Kerstin Bluhm, Xingzhong Yuan, Martina Roß-Nickoll, Andreas Schäffer, Henner Hollert
Besides obvious benefits, the Three Gorges Dam's construction resulted in new pollution scenarios with the potentials to threaten the Three Gorges Reservoir (TGR) ecosystem. In order to record organic contamination, to find links to ecotoxicological impacts and to serve as reference for ensuing monitoring, several sites in the TGR area were screened applying the triad approach with additional lines-of-evidence as a holistic assessment method. Sediments and the benthic fish species Pelteobagrus vachellii were sampled in 2011 and 2012 to determine organic pollution levels, mutagenic potentials and genotoxic impacts. Two regional hot-spots near the cities of Chongqing and Kaixian were identified and further investigated in 2013. Only polycyclic aromatic hydrocarbons (PAHs) could be detected in sediments in 2011 (165–1653ng/g), emphasizing their roles as key pollutants of the area. Their ubiquity was confirmed at Chongqing (150–433ng/g) and Kaixian (127–590ng/g) in 2013. Concentrations were comparable to other major Chinese and German rivers. However, the immense sediment influx suggested a deposition of 216–636kgPAH/day (0.2–0.6mgPAH/(m²·day)), indicating an ecotoxicological risk. PAH source analysis highlighted primary impacts of combustion sources on the more industrialized upper TGR section, whereas petrogenic sources dominated the mid-low section. Furthermore, sediment extracts from several sites exhibited significant activities of frameshift promutagens in the Ames fluctuation assay. Additionally, significant genotoxic impairments in erythrocytes of P. vachellii were detected (Chongqing/Kaixian), demonstrating the relevance of genotoxicity as an important mode of action in the TGR's fish. PAHs, their derivatives and non-target compounds are considered as main causative agents.

Graphical abstract

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Understanding actor-centered adaptation limits in smallholder agriculture in the Central American dry tropics

Abstract

Adaptations made by agrarian households in the face of global change risks are largely dependent on their livelihood goals. I argue that adaptation-limit research is crucial to many agrarian development programs because a focus on adaptation limits may allow researchers and practitioners to better understand and support successful adaptation and allow smallholders to pursue their goals. In this study of smallholder farming in Northwest Costa Rica, I found that security and the unique parcelero identity of rice farmers in this region define livelihood goals. I show that an understanding of the multidimensionality and fluidity of farmer livelihood goals may enrich our current understanding of actor-centered adaptation limits as insurmountable thresholds. In response to worsening global change risks, farmers in this study traded off certain goals to pursue others. In this way, farmers do not perceive adaptation limits as insurmountable. Alternative indicators of adaptation limits did exist; irreversibility in adaptation and the great hardship associated with tradeoffs among livelihood goals may mark adaptation limits.

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Can M. Aybek, Johannes Huinink, Raya Muttarak (Eds): Spatial Mobility, Migration, and Living Arrangements

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Referees

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Labor Market Laws and Intra-European Migration: The Role of the State in Shaping Destination Choices

Abstract

This article investigates the relationship between migrants' destination choices and the formal labor market access afforded by multiple potential host countries in the context of the EU's eastward enlargement. We use an index of labor market access laws combined with data on migration from new EU member states into the existing states of the EU and EFTA from 2004 through 2010 to test whether (1) migrants are attracted to destinations that give them greater formal labor market access, (2) migration flows to any given destination are influenced by the labor market policies of competing destinations, and (3) the influence of labor market laws on migrant flows is mediated by social networks, language ability, and educational level. Our data support the first two propositions and partly support the third: Migration between origin/destination pairs was positively associated with the loosening of destination labor market restrictions, while negatively associated with the loosening of competing destinations' labor market restrictions. In addition, the influence of destination labor market access appears to be weaker for destinations in which migrants have larger existing co-national networks, and for migrants from countries with languages that are more similar to the destination language, although we do not discern a clear mediating effect of education level. Our models also include variables for a set of economic indicators, social welfare spending, geographic distance, and historical relationships, and the estimated coefficients on these variables are largely in line with theoretical predictions. By combining rich EU data with a unique approach to evaluating competing legal regimes, the analysis helps us better understand how law shapes migration in a multi-destination world.

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Life Paths of Migrants: A Sequence Analysis of Polish Migrants’ Family Life Trajectories

Abstract

After Poland's accession to the European Union in 2004, Polish migration within Europe has increased considerably. Still, little is known about this large and growing group of immigrants. Using unique panel data from the Dutch population registers, we first apply sequence analysis to explore and describe the variety of family life courses among young adult (aged 20–30 at migration) Polish migrants in the Netherlands. Each individual family life career is followed for a 5-year period on a monthly time base. Optimal matching analysis is applied to compute (dis)similarities between individuals, in order to cluster into predominant life paths. Second, a series of logistic regression analyses were carried out to determine the main factors of importance on the different family life paths. Findings showed a strong impact of the partner's origin on the type of union and likelihood of return migration. Unemployment was found to be another important trigger of return migration. With regard to gender differences, we found that men are more likely to remain single and to leave the Netherlands at some point, while women more often cohabit and tend to stay.

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Demographic Issues of Intra-European Migration: Destinations, Family and Settlement

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Beyond l’Auberge Espagnole: The Effect of Individual Mobility on the Formation of Intra-European Couples

Abstract

This paper focuses on intra-European partnership formation in three European countries: Belgium, the Netherlands and Switzerland. Intra‐European mobility has been actively promoted and stimulated by the European Commission (e.g., free movement of persons, the Erasmus student exchange program). One of the reasons for this promotion is that exchanges and relationships between Europeans of different descent are seen as a core indicator of the success of the European project. In this paper, we address the question to what extent intra-European mobility fosters partnerships between Europeans of different descent. Intra-European mobility can create opportunities both to meet partners from other European countries and to accumulate the necessary capital (economic, cultural, linguistic, mobility) to engage in a relationship with a foreign European. We use original data on European (binational) couples, collected in 2012 in the three countries (EUMARR survey), to study the choice of native men and women to engage in a relationship with either a foreign-born European partner or a partner from the own native country. We apply a broader life course perspective that captures migration and mobility experiences prior to the relationship as causal antecedents leading to an intra-European partnership. Results based on logistic regression models suggest that there is an individual effect of long stays abroad and short mobility experiences in (early) adulthood on having an intra-European partner (in comparison with a native partner).

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Between Flows and Places: Using Geodemographics to Explore EU Migration Across Neighbourhoods in Britain

Abstract

During the past decade, the growing significance of EU migrants in Britain has attracted considerable media and policy attention. While the rhetoric and public policy debate has focused on national and regional levels, surprisingly, little is known about the emerging settlement patterns of EU migrants at the local level. This paper sheds some light on this important issue by exploring the socio-spatial characteristics of the places of destination/residence of EU migrants and, in doing so, reveals the extent to which the concentration-dispersal framework applies to their settlement pattern. To evaluate whether and in what ways EU migrants have settled across neighbourhoods in Britain, 2001 and 2011 census estimates as well as geodemographic data are used. The findings suggest that EU migrants have consolidated their national presence in Britain because of their growing numbers and unprecedented geographical dispersal. While EU migrants' settlement does not seem to translate into strong clustering patterns, diverging socio-spatial experiences are found among the largest groups (Polish, Italian, Portuguese and Spanish).

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Economic inequality and growth before the industrial revolution: the case of the Low Countries (fourteenth to nineteenth centuries)

This article studies a collection of data on economic inequality in fifteen towns in the Southern and Northern Low Countries from the late Middle Ages until the end of the nineteenth century. By using a single and consistent source type and adopting a uniform methodology, it is possible to study levels of urban economic inequality across time and place comparatively. The results indicate a clear growth in economic inequality in the two centuries prior to the industrial revolution and the onset of sustained economic growth per capita. The results presented lend support to the "classical" explanation of inequality as the consequence of a changing functional distribution of income favoring capital over labor over the course of the early modern period. These findings provide an alternative resolution of the conundrum presented by "optimist" and "pessimists" interpretations of early modern economic development.

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Ship speeds during the Industrial Revolution: East India Company ships, 1770-1828

The duration of voyages to Asia by English East India Company ships fell by a quarter to a third between the 1770s and the 1820s. The adoption of copper sheathing was the main reason for faster passages and worked through two channels. The more direct was to increase sailing speed by about 11 percent. The indirect, but quantitatively more important, effect was to eliminate the need for a stop at or near the Cape. These results show that there were significant improvements in shipping technology well before the use of steam and iron.

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Why did the National Industrial Recovery Act fail?

The National Industrial Recovery Act purportedly failed because it raised real wages and lowered employment. Beaudreau on the other hand argued that it should be seen as a policy response to technological change-based excess capacity and insufficient purchasing power. However, if wages lagged behind productivity growth, why did the National Industrial Recovery Act fail to increase employment and output? This article shows that the chosen policy instruments (e.g., Codes of Fair Competition and the President's Reemployment Agreement), and not the objectives, were among the causes of its demise. Across-the-board wage increases in the presence of firm and industry heterogeneity contributed to its demise.

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All equal in the sight of God: economic inequality and religion in the early twentieth century

A link between religion, estate division behavior, and economic inequality is demonstrated. Economic inequality varied across religious affiliations in early twentieth century Canada. Wealth inequality was higher for Anglicans and Roman Catholics relative to Presbyterians. Earnings inequality was higher for Anglicans and Presbyterians relative to Baptists and Catholics. In explaining differences in wealth inequality, estate division differences across religions are a factor with partibility associated with less inequality. However, these differences cannot be neatly categorized into watertight compartments according to the effects of differences in salvific merit or liberal/conservative divides suggesting the simple act of belonging had important network effects.

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Democracy, extension of suffrage, and redistribution in nineteenth-century Europe

The recent literature on democratization has traced this process back to the extension of suffrage. However, democratization concerns different aspects, not only the extension of suffrage, but also the extent of the powers of parliament. These two different dimensions of democracy are interdependent and can even be opposed. We show that the political elite may grant universal suffrage to counter pressure exerted by the bourgeoisie in favor of a widening of the powers of the parliament. By extending suffrage to the masses, the political elite makes it less advantageous for the bourgeoisie to seek a more powerful parliament. However, the entry, even in a parliament without powers, of representatives of the working class leads the political elite to ensure some form of redistribution. The historical experiences of some Western European countries during the nineteenth century and in the early twentieth century confirm this thesis.

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Market potential and regional economic growth in Spain (1860-1930)

In this study, parametric and nonparametric techniques are employed to analyze the effect of changes in regional market potential on the growth of Spanish regions during the period 1860–1930. The study of Spain sheds light on whether the construction of new transport infrastructures coupled with changes in trade policy ultimately shaped regional growth trajectories. The study draws upon new evidence of per capita gross domestic product for Spanish provinces and combines this evidence with Harris' market-potential function to measure regional market potential. Results show that market potential had a positive influence on regional economic growth, particularly between 1900 and 1930.

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