Brain Drain and Institutions of Governance: Educational Attainment of Immigrants to the US 1988-1998

We investigate the impact of home country institutions on the skill level of immigrants to the United States over 1988-1998. Specifically, we explore the hypothesis that institutions are multidimensional and that the different dimensions have conflicting impacts on the migration of skilled labor. Using an exploratory factor analysis on fifteen institutional variables, we identify the following dimensions of institutional character: credibility; transparency; democracy; and the security of civil society. We find that credibility and transparency increase the magnitude of brain drain; security reduces it; and democracy has no significant impact.immigration, institutions, political instability, brain drain

Gender bias and the female brain drain

This paper contributes to the emerging literature on gender differences in the causes and consequences of brain drain. Differentiating between gender bias in the access to economic opportunities and gender differentials in economic outcomes, we find that differences in access have a significant impact on the emigration of highly-skilled women relative to that of men. However, differentials in outcomes do not have a significant impact. Additionally, the structure of political institutions in the source countries does not have a significant impact on the difference in emigration rates.immigration, gender, brain drain

Brain Drain and Institutions of Governance: Educational Attainment of Immigrants to the US 1988-2000

We use a fixed effects panel data model to investigate the impact of institutions of governance on the educational attainment of immigrants to the United States over the period 1988 – 2000. Distinguishing between the quality and stability of political institutions in the countries of origin, we find that the two characteristics of institutional structure have conflicting impacts on the nature of brain drain. Immigrants from countries with a higher quality of political institutions tend to be better educated, on the average, than immigrants from countries with institutions of lower quality. However, immigrants from countries with greater political instability tend to be better educated than immigrants from countries with more stable governments.Immigration, institutions, political instability, brain drain

Civil War, Ethnicity, and the Migration of Skilled Labor

We investigate the impact of civil war on high skilled emigration rates to the OECD over the period 1985-2000. Controlling for economic and institutional characteristics of source countries, we find that civil war increases high skilled emigration by about 5 percent on the average. However, the nature of conflict matters: While brain drain from countries with ethnic conflict is about 6-8 percent greater on average than it is from countries without conflict, brain drain from countries with nonethnic conflict is less, and statistically insignificant. Duration also matters: Each additional year of ethnic conflict worsens the brain drain by between 0.4 and 1 percent, whereas the effect of an additional year of nonethnic conflict is small and insignificant.

Financial Liberalization and the Brain Drain: A Panel Data Analysis

This paper explores the impact of financial liberalization on the migration of high skilled labor from 46 countries to the OECD, taken at five year intervals over the period 1985-2000. Using an exploratory factor analysis, we are able to distinguish between two dimensions of financial liberalization, namely the robustness of the markets and their freedom from direct government control. We find that a standard deviation improvement in the robustness of the source country financial sector magnifies the extent of brain drain by a factor of about four percentage points on the average. However, a corresponding increase in the freedom of the source country financial sector from government control has a modest negative impact on the emigration of high skilled labor and the effect is not statistically significant. Further, the impact of improved financial sector robustness on selection is more pronounced for non-OECD economies than for OECD nations, which experience virtually no impact on skilled emigration.immigration, financial liberalization, brain drain, institutions

Blood Pressure Modifies Retinal Susceptibility to Intraocular Pressure Elevation

Primary open angle glaucoma affects more than 67 million people. Elevated intraocular pressure (IOP) is a risk factor for glaucoma and may reduce nutrient availability by decreasing ocular perfusion pressure (OPP). An interaction between arterial blood pressure and IOP determines OPP; but the exact contribution that these factors have for retinal function is not fully understood. Here we sought to determine how acute modifications of arterial pressure will affect the susceptibility of neuronal function and blood flow to IOP challenge. Anaesthetized (ketamine:xylazine) Long-Evan rats with low (∼60 mmHg, sodium nitroprusside infusion), moderate (∼100 mmHg, saline), or high levels (∼160 mmHg, angiotensin II) of mean arterial pressure (MAP, n = 5–10 per group) were subjected to IOP challenge (10–120 mmHg, 5 mmHg steps every 3 minutes). Electroretinograms were measured at each IOP step to assess bipolar cell (b-wave) and inner retinal function (scotopic threshold response or STR). Ocular blood flow was measured using laser-Doppler flowmetry in groups with similar MAP level and the same IOP challenge protocol. Both b-wave and STR amplitudes decreased with IOP elevation. Retinal function was less susceptible to IOP challenge when MAP was high, whereas the converse was true for low MAP. Consistent with the effects on retinal function, higher IOP was needed to attenuated ocular blood flow in animals with higher MAP. The susceptibility of retinal function to IOP challenge can be ameliorated by acute high BP, and exacerbated by low BP. This is partially mediated by modifications in ocular blood flow

Production of Interferons and β-Chemokines by Placental Trophoblasts of HIV-1-Infected Women

Objective: The mechanism whereby the placental cells of a human immunodeficiency virus (HIV)-1-infected mother protect the fetus from HIV-1 infection is unclear. Interferons (IFNs) inhibit the replication of viruses by acting at various stages of the life cycle and may play a role in protecting against vertical transmission of HIV-1. In addition the β-chemokines RANTES (regulated on activation T cell expressed and secreted), macrophage inflammatory protein-1-α (MIP-1α), and MIP-1β can block HIV-1 entry into cells by preventing the binding of the macrophage-trophic HIV-1 strains to the coreceptorCCR5. In this study the production of IFNs and β-chemokines by placental trophoblasts of HIV-1-infected women who were HIV-1 non-transmitters was examined. Methods: Placental trophoblastic cells were isolated from 29 HIV-1-infected and 10 control subjects. Supernatants of trophoblast cultures were tested for the production of IFNs and β-chemokines by enzyme linked immunosorbent assay (ELISA). Additionally, HIV-1-gag and IFN-β transcripts were determined by a semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) assay. Results: All placental trophoblasts of HIV-1-infected women contained HIV-1-gag transcripts. There were no statistical differences in the median constitutive levels of IFN-α and IFN-γ produced by trophoblasts of HIV-1- infected and control subjects. In contrast, trophoblasts of HIV-1-infected women constitutively produced significantly higher levels of IFN-β protein than trophoblasts of control subjects. Furthermore, the median levels of β-chemokines produced by trophoblasts of HIV-infected and control women were similar. Conclusions: Since there was no correlation between the placental HIV load and the production of interferons or β-chemokines, the role of trophoblast-derived IFNs and β-chemokines in protecting the fetus from infection with HIV-1 is not clear

Quantum heuristic algorithm for traveling salesman problem

We propose a quantum heuristic algorithm to solve a traveling salesman problem by generalizing Grover search. Sufficient conditions are derived to greatly enhance the probability of finding the tours with extremal costs, reaching almost to unity and they are shown characterized by statistical properties of tour costs. In particular for a Gaussian distribution of the tours along the cost we show that the quantum algorithm exhibits the quadratic speedup of its classical counterpart, similarly to Grover search.Comment: Published versio

Ecological Modeling of Aedes aegypti (L.) Pupal Production in Rural Kamphaeng Phet, Thailand

Background - Aedes aegypti (L.) is the primary vector of dengue, the most important arboviral infection globally. Until an effective vaccine is licensed and rigorously administered, Ae. aegypti control remains the principal tool in preventing and curtailing dengue transmission. Accurate predictions of vector populations are required to assess control methods and develop effective population reduction strategies. Ae. aegypti develops primarily in artificial water holding containers. Release recapture studies indicate that most adult Ae. aegypti do not disperse over long distances. We expect, therefore, that containers in an area of high development site density are more likely to be oviposition sites and to be more frequently used as oviposition sites than containers that are relatively isolated from other development sites. After accounting for individual container characteristics, containers more frequently used as oviposition sites are likely to produce adult mosquitoes consistently and at a higher rate. To this point, most studies of Ae. aegypti populations ignore the spatial density of larval development sites. Methodology - Pupal surveys were carried out from 2004 to 2007 in rural Kamphaeng Phet, Thailand. In total, 84,840 samples of water holding containers were used to estimate model parameters. Regression modeling was used to assess the effect of larval development site density, access to piped water, and seasonal variation on container productivity. A varying-coefficients model was employed to account for the large differences in productivity between container types. A two-part modeling structure, called a hurdle model, accounts for the large number of zeroes and overdispersion present in pupal population counts. Findings - The number of suitable larval development sites and their density in the environment were the primary determinants of the distribution and abundance of Ae. aegypti pupae. The productivity of most container types increased significantly as habitat density increased. An ecological approach, accounting for development site density, is appropriate for predicting Ae. aegypti population levels and developing efficient vector control program

A Cognitive Model of an Epistemic Community: Mapping the Dynamics of Shallow Lake Ecosystems

We used fuzzy cognitive mapping (FCM) to develop a generic shallow lake ecosystem model by augmenting the individual cognitive maps drawn by 8 scientists working in the area of shallow lake ecology. We calculated graph theoretical indices of the individual cognitive maps and the collective cognitive map produced by augmentation. The graph theoretical indices revealed internal cycles showing non-linear dynamics in the shallow lake ecosystem. The ecological processes were organized democratically without a top-down hierarchical structure. The steady state condition of the generic model was a characteristic turbid shallow lake ecosystem since there were no dynamic environmental changes that could cause shifts between a turbid and a clearwater state, and the generic model indicated that only a dynamic disturbance regime could maintain the clearwater state. The model developed herein captured the empirical behavior of shallow lakes, and contained the basic model of the Alternative Stable States Theory. In addition, our model expanded the basic model by quantifying the relative effects of connections and by extending it. In our expanded model we ran 4 simulations: harvesting submerged plants, nutrient reduction, fish removal without nutrient reduction, and biomanipulation. Only biomanipulation, which included fish removal and nutrient reduction, had the potential to shift the turbid state into clearwater state. The structure and relationships in the generic model as well as the outcomes of the management simulations were supported by actual field studies in shallow lake ecosystems. Thus, fuzzy cognitive mapping methodology enabled us to understand the complex structure of shallow lake ecosystems as a whole and obtain a valid generic model based on tacit knowledge of experts in the field.Comment: 24 pages, 5 Figure