Repulsive Factors Research Articles

Chimera states in fractional-order coupled Rayleigh oscillators

Chimera states, characterized by the coexistence of synchronized and desynchronized oscillators, have been extensively described via integer differential equations over the past few decades. However, it is still unclear whether and under which conditions chimera states will appear in terms of the coupled systems involving fractional derivatives. In this work, we investigate the chimera states of Rayleigh oscillators in the fractional-order systems with attractive and repulsive couplings. Firstly, we introduce the repulsive control factor and show the various transition routes from the desynchronized state to the incoherent oscillation death by altering this factor and the fractional-order derivatives. Then, it is demonstrated that as the coupling strength varies, a vast repertoire of interesting collective behaviors will emerge, such as synchronization, solitary state, traveling wave, traveling chimera, oscillatory cluster, imperfect traveling chimera state, imperfect amplitude chimera state, and chimera death. Finally, we discuss the effect of attractive and repulsive couplings and find that decreasing the repulsive control factor can reduce the repulsive interaction, allowing the attractive coupling to dominate and promote the emergence of the coherent state.

A Jamming Aware Artificial Potential Field Method to Counter GPS Jamming for Unmanned Surface Ship Path Planning

Global positioning system (GPS) plays an important role in the path planning of unmanned surface ships. As we know, the civil GPS signal is not encrypted, and its structure is open. Meanwhile, the power strength of GPS signals arriving at receivers is weak. All of these make GPS vulnerable to jamming. GPS jamming attacks adversely affect the accuracy of the received GPS signals, thus affecting the path planning results of unmanned surface ships and even causing collisions. This article presents a jamming aware artificial potential field (JA-APF) method. The JA-APF method first determines whether GPS jamming exists in unmanned surface ships' surrounding environment by detecting the receivers' received signal strength and calculating the packet error rate. Then, the JA-APF method calculates the position range of the jamming source. Finally, the JA-APF method replans the path according to the resultant force of the attraction around the goal, the repulsion around obstacles, and the repulsion around multiple GPS jammers. Through the simulation, we determine the value of the repulsive potential factor of the jammer to optimize the path planning results of the JA-APF method and analyze the influence of the jamming power on the path planning results. The simulation results show that the JA-APF method can effectively solve the impact of GPS jamming on the results in the path planning process and recover as soon as possible.

Reasons for choosing Russia as the main direction of labor migration from Tajikistan in the context of COVID-19 pandemic and sanctions

The article examines the impact of the currency crisis and the consequences of COVID-19 pandemic on labor migration from Tajikistan to Russia, the impact of new anti-Russian sanctions by the European Union and United States of America on Tajik labor migrants, as well as the repulsive factors of the reorientation of migrants from Tajikistan to a new direction of labor emigration to the Organization for Economic Co-operation and Development (OECD) countries and the Persian Gulf. Russia is the main migration channel for labor migrants from Tajikistan. During the entire period of their stay in Russia they face various crisis phenomena in the country along with the local population. Each crisis in Russia has had a different negative impact on the situation of Tajik labor migrants. During the currency crisis in 2014–2015, Tajik migrants lost their income by twice due to the fall in the Russian ruble exchange rate. During the COVID-19 period, because of the introduction of a self-isolation regime in Russia, since the end of March 2020, the Russian labor market has been compressed, many Tajik labor migrants have lost their jobs. The new anti-Russian sanctions have already affected Tajikistan. Due to the European and the United States sanctions against Russia, the total flow of labor migration from Tajikistan to Russia has decreased. The aim of the article is to identify the attractive factors of the orientation of Tajik migrants to labor emigration to Russia and the repulsive factors of the reorientation of Tajik migrants to a new direction of labor emigration to the OECD and Persian Gulf countries.

Az immobilitást növelő és csökkentő települési jellemzők


 
 
 The study looks for answers to the question: what are the reasons behind staying in small mu- nicipalities, especially in highly disadvantaged villages, when moving into cities offers obvious advantages. We have analysed the motives, as well as attractive and repulsive factors based on 104 interviews, in case of 13 municipalities. The interviews convincingly certify that the decision about moving or staying in one place is a complex, multifactorial process. In this, employment opportunities have an undeniably important, however, not completely exclusive role. It is cor- related with the demographic characteristics, gender, age, family status, labour market para- meters, education level, financial characteristics, individual peculiarities, health status of the individual, as well as with its attitude towards changes, ethnic background, and its contentment concerning the given settlement.
 
 

On the nature of inter-anion coinage bonds.

To explore the binding energy profiles and elucidate the bonding nature in counter-intuitive anion⋯anion coinage bonds (CiBs), thirty-one complexes were constructed, and the inter-anion CiBs were studied theoretically. The metastability was evidenced by the characteristic potential wells in six cases, demonstrating that anions [Au(CN)4]-, [Ag(CN)2]- and [AuO]- are appropriate building blocks for CiBs. The kinetic stability was further supported by ab initio molecular dynamics (AIMD) simulations and the analyses based on the local vibrational mode and quantum theory of atoms in molecules (QTAIM) methods. The anion⋯anion CiBs in the dimers of [AuCl4]- and [Au(CN)4]- previously observed in condensed phases were confirmed to be thoroughly repulsive under vacuum, but turned attractive in the crystal environment which was simulated using the solvation model based on density (SMD). However, the intrinsic strength of the inter-anion bonding is barely variated by the environment, as it is the combination of the inter-anion interaction and the environment effect that stabilizes the anion pairs. The block-localized wavefunction (BLW) method and its corresponding energy decomposition (BLW-ED) approach were further employed aiming at a chemically meaningful explanation for these counterintuitive phenomena. By inspecting the profiles of energy components, we identified the vital distinction between inter-anion CiBs and conventional non-covalent interactions lying in the electrostatic interaction, which variates nonmonotonically in the inter-anion complexes. The electrostatic interaction also dominates the depth of potential wells, which is commonly used to evaluate the kinetic stability, while Pauli exchange repulsion is the most repulsive factor preventing the formation of anion adducts. The importance of the Pauli exchange repulsion was further highlighted by comparing cases with and without metastability, in which the absence of a potential well is solely caused by the enhancement of the Pauli exchange repulsion.

Forecasting power load: A hybrid forecasting method with intelligent data processing and optimized artificial intelligence

An accurate power load prediction in smart grid plays an important role in maintaining the balance between power supply and demand and thus ensuring the safe and stable operation of power system. In this paper we develop a hybrid power load prediction method, which involves three main steps: data decomposition with the empirical mode decomposition method, data processes with the minimal redundancy maximal relevance method and the weighted gray relationship projection algorithm, and support vector machine prediction, whose parameters are optimized through the particle swarm optimization algorithm with a second-order oscillation and repulsive force factor. Moreover, we predict the power load with our hybrid forecasting method based on the real dataset from the electricity market in Singapore, and also compare our prediction results with those by using other forecasting methods. Our comparison results show that our novel hybrid method possesses a high accuracy in both the level and directional predictions.

Interactions, Diffusion, and Membrane Fluctuations in Concentrated Unilamellar Lipid Vesicle Solutions

Lipid vesicles are widely used as models for cell membranes, hosts for membrane protein studies, and containers for hydrophilic molecules. The vesicle solutions in these applications are usually prepared at a specific lipid concentration; however, because vesicles are solvent-filled structures, the corresponding volume fraction of vesicles is at least a factor of three times higher than the corresponding lipid volume fraction and critically depends on the vesicle radii. Here we show that these higher than may be expected vesicle volume fractions result in measurable interactions between the vesicles as well as affect the vesicle diffusion. We show that vesicle solutions prepared with lipid mass fractions, mL, as low as ≈ 0.004, which correspond to a lipid concentration of ≈ 4 mg/mL or 5 mmol/L (mM), not only have a measurable apparent structure factor (S′(q)) in small angle neutron scattering (SANS) experiments, but that this repulsive structure factor also affects the measured diffusion coefficient at small scattering vectors (q) such as those probed with dynamic light scattering (DLS). The measured diffusion coefficients are further affected by indirect solvent mediated interactions described by a hydrodynamic factor (H(q)). Accounting for the concentration-dependence of the vesicle diffusion shows that the lipid concentration dependence measured in neutron spin echo (NSE) spectroscopy is due to differences in the effective vesicle diffusion coefficients and not the membrane fluctuation dynamics. The results have practical implications for static and dynamic scattering experiments as well as provide interesting insights into the interactions between soft lipid vesicles.

Attractiveness of Russian Universities among Foreign Students in Conditions of Competitive Global Markets of Educational Services

Introduction. Many foreign students study at universities in the provincial regions of Russia. At the same time, research into criteria and factors that influenced the choice of a Russian regional university among foreign students have not been carried out until now. The main purpose of the study is to identify the criteria and factors of the attractiveness of a university located not in the capital region, but on the periphery of Russia, according to foreign students. Materials and Methods. Stages of the research: analysis of statistics on the number of foreign students in Russia, analysis and generalization of literary sources in the field of identifying the motives of applicants when making a decision to study at a foreign university, a sociological survey of foreign students studying at universities in the Volga Federal District, processing and generalization of the survey results, development of recommendations to increase the attractiveness of Russian higher education for foreign applicants. Results. According to the results of a sociological survey among foreign students studying at universities of the Volga Federal District, the attractive factors of choosing Russia as a country for higher education, as well as repulsive (negative) factors in their native country, were revealed. The reasons and goals of admission to the Russian university, the sources of information about Russia and the university, the criteria for choosing a Russian university were analyzed, the strategic goals of foreign students after graduation were identified. Discussion and Conclusion. The conclusions made by the authors contribute to the development of theoretical approaches and methodological tools for studying the choice of foreign universities by foreign students for their studies, identifying the motives and factors that influenced this choice. The materials of the article will be useful to scientists and researchers dealing with such problems, as well as to federal and regional governments, ministries of education, regional universities in developing programs to increase the international competitiveness of higher education in Russia and attract an international contingent of students.

Način života i potrebe mladih u selima Pčinjske oblasti - primer sela Tibužde, Rataje i Vrtogoš

The majority of rural youth do not see their strengths and opportunities for progress from socially rooted family relationships, as well as from the place of living. As such, together with the city's youth, is on the edge of Serbian society's system. Faced with numerous problems and accompanying phenomena, such as the prolonged youth due to education or the economic dependence on parents, the feeling of deprivation dominates among the rural youth, i.e. the state of completely or insufficiently fulfilled psychological, social or emotional needs. Migration of rural youth is generally one of the biggest issues of rural areas all over the world, including Serbia. A number of reasons attract rural youth population to the city (so-called pull factors): better livelihood prospects, a greater offer of jobs, higher level of earnings, entertainment contents, better opportunities for professional success, anonymity as well as a variety of goods and services, etc. The repulsive factors found in the countryside (the so-called push factors) are: shortage of arable land, unemployment, low and uncertain income and level of earnings, social control and dependence, monotony and boredom, insufficiently diverse offer of goods and services, etc. On the other hand, those who do not speak in favor of resettlement see the village as a place of greater freedom and peace.

Exploring Cloud Computing Readiness and Acceptance in Higher Education Institution: A PLS-SEM Approach

Abstract: The COVID-19 pandemic has altered nearly every aspect of life, including education. Technology has replaced face-to-face teaching and learning nearly totally. This health disaster has accelerated digitization in the world of education, which was previously only available without a repulsive factor. Cloud computing technology has been widely used in education, including higher education, enabling teaching resources, educational information, notes, lectures, and academic assessments to be accessed and shared online. Yet, in celebrating the greatness of technology, are users ready to accept an explosion of information resources and access openly online through cloud-based services? Thus, this research will investigate the Higher Education Institution (HEI) users' readiness and acceptance of cloud computing. The research employs the Technology Acceptance Model (TAM) and Technology Readiness Index (TRI) model together with Structural Equation Modeling (SEM) to investigate 470 individuals from HEIs in Malaysia. Perceived Ease of Use and Perceived Usefulness are found to be positively significant in explaining why a user decides to use cloud computing. Optimism and innovativeness have found to affect the factors of technology acceptance significantly. In contrast, discomfort and insecurity do not affect technology acceptance factors, except for insecurity that negatively impacts Perceived Usefulness. This study contributes to another finding to studying technology readiness and acceptance, especially in higher education.
 
 Keywords: Cloud Computing, Technology Readiness, Technology Acceptance, HEI, SEM

I servizi nelle Alpi italiane: quali e dove? Idee per uno scenario post-pandemico

In the rural mountains, middle-lower level services (general practitioners, pharmacies, schools, supermarkets, etc.) play a crucial role. However, in the Italian Alps they only exist in a third of the municipalities, almost located in the low valleys. The few centers which include these essential functions and located in the innermost regions are those that ensure basic conditions of habitability for 45% of the Italian Alpine municipalities: they are the municipalities of the territories classified by the report Montagne Italia 2017 as “extreme” and “rarefied”. Welfare interventions must take into account this particular distribution of supply centers, their gravitations, the consequent demand for collective transport and the alternatives offered by teleservices. With the pandemic, the scenario changes. It can be assumed that the attractive factors of mountain areas and the repulsive factors of the city will both be enhanced. It is likely that the demand for services, mobility and digital infrastructures will tend to change the composition and distribution of the offer, with particularly significant effects on the Alpine municipalities of the internal mountain and on the centers within residents gravitate. Head alpine cities already serve a large number of inhabitants, which include residents and tourists; this is why these effects will be noticeable elsewhere, most of all in the appearance of important factors in the “functional upgrading” of smaller alpine cities and semi-urban foothill centers.

ОРГАНИЗАЦИОННО-ЭКОНОМИЧЕСКИЙ МЕХАНИЗМ РЕГУЛИРОВАНИЯ МИГРАЦИИ ТРУДОСПОСОБНОГО СЕЛЬСКОГО НАСЕЛЕНИЯ В РЕГИОНЕ

A mechanism has been developed to regulate the migration of the able-bodied rural population, taking into account the identified attractive and repulsive factors (income level, availability of medical services and general educational organizations) for groups of municipal districts depending on the level of demographic distress (depressed; partially depressed; border values that are borderline and successful). Through the mechanism for implementing decisions with regulatory support, taking into account municipal strategies for socio-economic development, a targeted administrative and managerial impact on business entities, the working population, social infrastructure and the socio-economic sphere of depressed, partially depressed, border and favorable regions of the region is substantiated. The mechanism is controlled by an interdepartmental commission on rural development under the relevant ministry (agriculture of the region) and is carried out using the tools of the organizational and economic module. These tools provide: improvement of social infrastructure, social guarantees and transparency in the labor market, stable earnings, provision of housing for professionals through long-term labor contracts (at least 10 years), the allocation of enterprises own funds for free assistance for overhaul and maintenance of social infrastructure facilities, implementation of investment projects in the areas of specialization of differentiated groups of regions, including crop production (mainly vegetable farming of closed soil) and livestock farming (sheep, fish farming, poultry farming), as well as the modernization and revitalization of the production and processing infrastructure of the agro-industrial complex (grain crops, elevators, slaughter shops, deep processing workshops). The systemic impact of the mechanism will create 726 additional jobs in the agricultural sectors in the Baltay, Petrovsk, Turki, Voskresenskoe, Novouzensk and Krasnoarmeysk districts and reduce the existing outflow of the population.

Endosomal trafficking in human cortical neurons downstream of RTK signaling is defective in Tuberous Sclerosis

Growth cones at the distal tips of developing axons transduce extracellular chemoattractants and repellents into guided motility throughout developing organisms. Repulsive factors can produce abrupt cytoskeletal contraction in growth cones, coupled with internalization of plasma membrane in a process called “collapse”. Using neurons differentiated from induced pluripotent stem cells (iPSCs), we examine mechanisms that control normal human cortical neuron development and dysregulation of these signals in Tuberous Sclerosis Complex (TSC). TSC is a neurodevelopmental disorder caused by pathological variants of the genes encoding TSC1 or TSC2, resulting in the formation of cortical tubers and improper neuronal connectivity. These defects likely contribute to TSC neuropathology such as cognitive deficits, autism, and epilepsy. Using immunoassays and live cell imaging, our lab has shown that TSC2+/− neurons fail to respond the chemorepellent EphrinA1 in several quantifiable measures. TSC2+/− growth exhibit reduced rapid membrane internalization via macropinocytosis and show less elevated receptor tyrosine kinase signaling, as well as reduced cytoskeletal contraction and F‐actin depolymerization. Studies have shown that endocytosis and trafficking of receptor tyrosine kinase (RTK) signaling endosomes are required to elicit a proper guidance response. Immunoassays and live endosome imaging in TSC2+/− growth cones suggest normal EphrinA1‐EphA4 internalization, but defective endosome trafficking of EphrinA1 from early endosomes to late endosomes. Other experiments implicate defects in growth cone microtubule dynamics, a poorly understood but essential process for proper endosome trafficking and guidance cue responses. This research aims to improve our understanding of RTK endosome trafficking and show how defects in these processes can lead to neurodevelopmental disorders.

Semaphorin-3A Promotes Degradation of Fragile X Mental Retardation Protein in Growth Cones via the Ubiquitin-Proteasome Pathway.

Fragile X mental retardation protein (FMRP) is an RNA-binding protein that regulates local translation in dendrites and spines for synaptic plasticity. In axons, FMRP is implicated in axonal extension and axon guidance. We previously demonstrated the involvement of FMRP in growth cone collapse via a translation-dependent response to Semaphorin-3A (Sema3A), a repulsive axon guidance factor. In the case of attractive axon guidance factors, RNA-binding proteins such as zipcode binding protein 1 (ZBP1) accumulate towards the stimulated side of growth cones for local translation. However, it remains unclear how Sema3A effects FMRP localization in growth cones. Here, we show that levels of FMRP in growth cones of hippocampal neurons decreased after Sema3A stimulation. This decrease in FMRP was suppressed by the ubiquitin-activating enzyme E1 enzyme inhibitor PYR-41 and proteasome inhibitor MG132, suggesting that the ubiquitin-proteasome pathway is involved in Sema3A-induced FMRP degradation in growth cones. Moreover, the E1 enzyme or proteasome inhibitor suppressed Sema3A-induced increases in microtubule-associated protein 1B (MAP1B) in growth cones, suggesting that the ubiquitin-proteasome pathway promotes local translation of MAP1B, whose translation is mediated by FMRP. These inhibitors also blocked the Sema3A-induced growth cone collapse. Collectively, our results suggest that Sema3A promotes degradation of FMRP in growth cones through the ubiquitin-proteasome pathway, leading to growth cone collapse via local translation of MAP1B. These findings reveal a new mechanism of axon guidance regulation: degradation of the translational suppressor FMRP via the ubiquitin-proteasome pathway.

Diastereomeric Crowding Effects in the Competitive DNA Intercalation of Ru(phenanthroline)2dipyridophenazine2+ Enantiomers.

The biexponential excited-state emission decay characteristic of DNA intercalated tris-bidentate dppz-based ruthenium complexes of the general form Ru(L)2dppz2+ has previously been explained by a binding model with two distinct geometry orientations of the bound ligands, with a distinct lifetime associated with each orientation. However, it has been found that upon DNA binding of Ru(phen)2dppz2+ the fractions of short and long lifetimes are strongly dependent on environmental factors such as salt concentration and, in particular, temperature. Analyzing isothermal titration calorimetry for competitive binding of Ru(phen)2dppz2+ enantiomers to poly(dAdT)2, we find that a consistent binding model must assume that the short and long lifetimes states of intercalated complexes are in equilibrium and that this equilibrium is altered when neighboring bound ligands affect each other. The degree of intercomplex binding is found to be a subtle manifestation of several attractive and repulsive factors that are highly likely to directly reflect the strong diastereomeric difference in the binding enthalpy and entropy values. In addition, as the titration progresses and the binding sites on the DNA lattice become increasingly occupied, a general resistance for the saturation of the binding sites is observed, suggesting diastereomeric crowding of the neighboring bound ligands.

Balance between BDNF and Semaphorins gates the innervation of the mammary gland.

The innervation of the mammary gland is controlled by brain-derived neurotrophic factor (BDNF), and sexually dimorphic sequestering of BDNF by the truncated form of TrkB (TrkB.T1) directs male-specific axonal pruning in mice. It is unknown whether other cues modulate these processes. We detected specific, non-dimorphic, expression of Semaphorin family members in the mouse mammary gland, which signal through PlexinA4. PlexinA4 deletion in both female and male embryos caused developmental hyperinnervation of the gland, which could be reduced by genetic co-reduction of BDNF. Moreover, in males, PlexinA4 ablation delayed axonal pruning, independently of the initial levels of innervation. In support of this, in vitro reduction of BDNF induced axonal hypersensitivity to PlexinA4 signaling. Overall, our study shows that precise sensory innervation of the mammary gland is regulated by the balance between trophic and repulsive signaling. Upon inhibition of trophic signaling, these repulsive factors may promote axonal pruning.

A Critical Role of Host-Derived Semaphorin-4A for Regulating T Cell Immune Responses in Acute Graft Versus Host Disease

Semaphorins, originally identified as repulsive axon-guidance factors that participate in neuronal development. Several semaphorins are involved in various phases of immune responses, as has been shown recently. Semaphorin4A (Sema4A), a class IV transmembrane semaphorin, is preferentially expressed in dendritic cells (DCs) and Th1 cells. Previous studies suggested that Sema4A is involved in Ag-specific T cell priming, and in Th1 cell and Th17 cell differentiation. Additionally, Sema4A is required for the stability and function of Tregs. However, the role of Sema4A in alloimmune responses remains to be elucidated. In this study, we examined the contribution of Sema4A to T cell immune responses in the context of allogeneic hematopoietic stem cell transplantation (allo-HCT).To test the role of Sema4A in T cell proliferation, we performed in vitro T cell proliferation assay using dendritic cells harvested from wild-type or Sema4A-KO mice. Conventional CD4+T cells cocultured with DCs harvested from wild-type and Sema4A-KO mice proliferated equally in the presence of anti-CD3 antibody. In contrast, anti-CD3-induced proliferation of Tregs cocultured with DCs harvested from Sema4A-KO mice was attenuated compared to Tregs cocultured with DCs harvested from wild-type mice, suggesting that Sema4A is required for maximum proliferation of Tregs.We next investigated the effects of Sema4A deficiency in acute GVHD. We employed a murine acute GVHD model (B6→BALB/c) and monitored every day for survival. Body weight was assessed 2-3 times per week. First, to investigate the role of host Sema4A, lethally irradiated wild-type and Sema4A-KO mice were injected with T cell-depleted bone marrow cells and T cells isolated from wild-type B6. Sema4A-KO host mice developed significantly higher mortality compared to wild-type host mice (p<0.001) (Figure). On day 7 after allo-HCT, the proportion of Tregs in the spleen were significantly decreased in Sema4A-KO host mice compared to wild-type host mice (p<0.05). Both donor-derived preexisting natural Tregs and inducible Tregs in Sema4A-KO host mice were significantly decreased compared to wild-type host mice, although relatively less in inducible Tregs. We investigated the production of proinflammatory cytokines (IFN-g, IL-17, IL-4 and IL-13) of T cells in the spleen by intracellular cytokine staining. The proportion of IL-17+CD4+ T cells in Sema4A-KO host was slightly but not significantly decreased compared to wild-type host, whereas similar proportion of IFN-g+CD4+T cells was observed in Sema4A-KO and wild-type host mice. In contrast, the proportion of IL-4+CD4+ T cells in Sema4A-KO host was significantly increased in Sema4A-KO host mice compared to wild-type host mice, suggesting Sema4A deficiency skewed cytokine polarization of T cells after allo-HCT.Subsequently, we used Sema4A-KO and wild-type B6 mice donor to investigate the role of donor-derived Sema4A. Host mice transplanted from Sema4A-KO donor developed comparable mortality with host mice transplanted with wild-type donor, suggesting that donor-derived Sema4A does not play an important role in controlling graft versus host reactions in this model.Together, these results suggest that Sema4A contributes to Treg maintenance and the regulation of T cell responses after allo-HCT, which may have clinical implications for the novel approach in the treatment and protection of GVHD. [Display omitted] DisclosuresIto:Bristol-Myers Squibb: Honoraria, Research Funding; Takeda: Honoraria; Novartis Pharma: Honoraria; Pfizer: Honoraria; Mundipharma: Honoraria; Celgene: Honoraria.

The Impact of Competitiveness on Brain Drain, GMM Panel Approach

Brain drain is one of the challenges that many countries have been facing for ages and it is considered as one of the most damaging issues in the countries. So far, economists have always emphasized and focused on the factors affecting brain drain, including economic growth, quality of innovation, human capital, unemployment rate of graduates, institutional quality, intellectual property rights, economic, political and civil liberties, political and social environment, inequality, and so on. The study of each of them, in turn, explains the causes of brain drain. But along with these factors, the effect of the power of competitiveness on brain drain, which has recently been taken into consideration by international communities, has been neglected and there have not yet been comprehensive studies on it. While competitiveness as a factor of attraction can increase the motivation and welfare of the elites and it ultimately prevents the elites from leaving the country by employing them in different parts of the country. In this regard, the purpose of this study is to investigate the effect of competitiveness on brain drain from selected Islamic countries to the USA during the period from 2007 to 2015 using the Generalized Method of Moments (GMM). The results of this study showed that the competitiveness index has a negative and significant effect on brain drain. Additionally, the indexes of welfare gap and real wage gap have respectively positive, significant and positive, and insignificant relationships with brain drain in the studied countries. The variable of unemployment rate also has a positive and significant relationship with the brain drain. According to the findings of the study, poor competitiveness in Islamic countries, which are mostly sending countries, is a repulsive factor that leads to a large exodus of elites from the above-mentioned countries. Therefore, it is suggested that politicians and managers of the Islamic countries pay more attention to the indicators of competitiveness in order to reduce the brain drain.

Main Directions of Migration Mobility in the Siberian and Far Eastern Federal Districts

The article considers the migration mobility in the regions of Eastern Siberia and Russian Far East. The purpose of the study is to analyze and characterize the migration mobility of the population of the Siberian Federal District (SFD) and the Far Eastern Federal District (EFD) as well as to identify the interregional migration factors that determine the geography of its directions. The main hypothesis of the study is that interregional differences in the social and economic development of regions play a primary role in the formation of the repulsive and attractive factors of migration. We used statistical analysis and mathematical methods, as well as their geographical visualization. We have analyzed data from the Rosstat databases and have shown that migration losses in the SFD regions are significantly higher than in FEFD. However, for FEFD, these losses are more significant. Therefore, poorly populated and depressive regions deserve special attention. In these regions, even minimal migration losses considerably increase socio-demographic risks. We revealed that the indigenous population prevail in these territories. At the same time, the increasing territorial mobility of native inhabitants is observed. In most of the regions, there is a low migrant’s adaptation level. We have proposed the authors’ approach to the study of migration repulsive and attractive factors. It is based on the integration of the methods of multidimensional cluster analysis and geo-information analysis. This approach has allowed to classify the Russian regions in terms of their migration attractiveness as well as to show the geography of the prevailing migration movements for each region of SFD and FEFD. The results of the study have confirmed the dependence of migration mobility on the quality of life in different regions. These data may be applied to elaborate mechanisms for an effective policy of regional socio-economic development in the country. The promising direction for the further research is the application of our method at the municipal level. It may allow structuring regional economic spaces depending on the growth poles and the periphery.

Polarized Distribution of Active Myosin II Regulates Directional Migration of Cultured Olfactory Ensheathing Cells

Migration of olfactory ensheathing cells (OECs) is critical for development of olfactory system and essential for neural regeneration after OEC transplantation into nerve injury site. However, the molecular mechanisms underlying the regulation of directional migration of OECs remain unclear. In this study, we found that in migrating OECs, phosphorylated myosin light chain (p-MLC, active myosin II) displayed a polarized distribution, with the leading front exhibiting higher than soma and trailing process. Over-expression of GFP-MLC significantly reduced OEC migration. Moreover, decreasing this front-to-rear difference of myosin II activity by the frontal application of a ML-7 (myosin II inhibitors) gradient induced the collapse of leading front and reversed soma translocation of OECs, whereas, increasing this front-to-rear difference of myosin II activity by the rear application of a ML-7 or BDM gradient or the frontal application of a Caly (myosin II activator) gradient accelerated the soma translocation of OECs. Finally, myosin II as a downstream signaling of repulsive factor Slit-2 mediated the reversal of soma translocation induced by Slit-2. Taken together, these results suggest that the polarized distribution of active myosin II regulates the directional migration of OECs during spontaneous migration or upon to extracellular stimulation such as Slit-2.