Les branches d'hystérésis et les régimes transitionnels de la convection pénétrante dans la couche d'eau

L'interaction de régions stables et instables d'un fluide provoque un phénomène nommé 'la convection pénétrante' : des perturbations sortent de la région instable pour pénétrer dans la région stable. Nous examinons ce type de convection dans le cas d'une couche horizontale d'eau se trouvant à des températures proches de celle correspondant au maximum de densité. Nous imposons comme conditions aux limites des températures constantes et des contraintes tangentielles nulles. La dépendance densité-température est définie comme une fonction quadratique avec un maximum à 4°С [1]. Dans l'état conductif, deux sous-couches peuvent être définies, l'une est en dessous du plan horizontal de la densité maximale, l'autre est au dessus. La solution 2D est supposée être périodique spatialement en imposant des contraintes tangentielles nulles comme conditions aux limites verticales d'un domaine de périodicité. La longueur de période a été choisie grâce à des simulations préliminaires. Nous observons l'évolution des régimes avec l'augmentation du nombre de Rayleigh. La méthode pseudo-spectrale à été utilisée en faisant varier le nombre d'harmoniques de Fourier jusqu'à 1024x528. Les propriétés de l'apparition du mouvement sont étudiées, y compris des branches d'hystérésis. Sur l'une des branches la transition au chaos a lieu : après le mouvement périodique, la bifurcation souscritique de Neimark-Sacker se passe [2]. De ce fait, le régime quasi périodique devrait apparaître, mais en raison de la synchronisation des fréquences, le régime périodique-2 sur un tore apparaît. Ce régime est accompagné d'une perte de symétrie par rapport à la ligne verticale se trouvant au milieu du domaine de calcul. Ensuite, des régimes quasi périodiques se manifestent. Pour la convection classique de Rayleigh-Bénard, l'intermittence existe sur un fond de régime périodique [3], mais dans notre cas elle existe sur un fond de mouvement quasi périodique. Après l'intermittence, un nouveau régime quasi périodique apparaît. Puis l'intermittence se manifeste de nouveau. L'étude a été soutenue par RFBR, projet 12-01-31460. Références 1. Veronis G. 1963. Astrophys.J. 137, 641-663. 2. Kuznetsova D., Sibgatullin I. 2012. Fluid Dyn.Res. 44, 031410. 3. Bergé P., Dubois M., Manneville P., Pomeau Y. 1980. Phys.Lett. 41, L341-L345

Public consumption in the context of sustainable development: requirement for modernization

Article deals with basic features of current system of consumption and its incompatibility with the principles of sustainable development. The analyses argues for necessity of forming the new model of consumption, proposes its principles aimed to achieving balanced economic, social and environmental development

Impact of the decentralization reform on the quality of local public services in Ukraine

Decentralization, the transfer of authorities from the central government to local governments, tends to impact the performance of local authorities. These impacts are felt through changes in the allocation of revenue patterns, improvements to the quality of, and access to, public services, and relocation of decision-making to a local level. The ongoing decentralization reform in Ukraine simultaneously features administrative, fiscal and political decentralization of power. It is expected that the reform will facilitate community development and improve quality of life by empowering the lowest levels of government. This study analyzes changes in the quality of public services in the cities of regional significance in Ukraine since the beginning of the decentralization reform in 2014. Using the data from the Ukrainian Municipal Survey 2015-2018, we compared the quality of public services rated by the residents of the 24 cities in 2015 and 2018. We found that the overall quality of public services improved within the measured period with only the quality of medical institutions showing a slight decrease. The largest improvements were observed in the quality of road infrastructure and public parks. We attribute these improvements to increased government transparency and accountability, as well as local governments’ ability to address local issues. Increased revenues and reductions in corruption also contributed to the improvement in the quality of public services. However, regardless of the improved average quality, some cities show significant decreases in some, or most, of the services. Among the 24 surveyed cities, 18 improved the average quality of public services. The citizens of the remaining six cities rated the quality as decreased. The estimated decreases vary from 0.9% in Ternopil to 9.1% in Chernivtsi. Based on the inconsistency in the change of the quality of public services, we recommend a process for monitoring of actions, expenditures, and budgets at local levels of government, linked with their actions for improving the quality of local services. Secondly, local governments should facilitate actions that address the current low level of public participation and engagement in local decision-making. Additionally, shifting the responsibility of providing public services from local governments to private companies and implementation of public-private partnerships will ensure more consumer oriented services, and therefore, higher quality of services due to market competition. Lastly, we call for well-trained officials to support comprehensive planning and economic development planning efforts in local governments

Cartographic analysis of woodlice fauna of the former USSR

An inventory of the woodlice fauna of the former USSR yielded 190 species, 64 of them were recorded from the territory of Russia. According to the cartographic analysis, the limits of distribution of epigean terrestrial isopods over the area, excluding mountains, is explained by temperature. No woodlice records were found outside the isocline of 120 days a year with the mean daily air temperature >10°C. The highest species diversity was found between the isoclines of 180 and 210 days. These areas correspond to forest-steppe and steppe zones

Europeanization of youth policy : case study of Finland and Norway

Youth policy is a relatively young topic for International Relations. Nevertheless, it becomes more relevant at the European level. There is an evolution and growing quantity of youth related strategies, programmes, acts and policies both at the European and domestic levels. For Europe, the youth can be a resource to support cooperation, smart economy and sustainable development. This Master’s Thesis argues that the European youth dimension has particular impact on domestic youth policies. This thesis inquires how European integration appears in the youth policy, and discovers causal relations between European and domestic policy changes. The object of this research is youth policy, and the subject is its evolution and changes due to European integration. It is possible to look at the youth dimension through the lens of Europeanization theory, and its narrower type – EU-ization. This thesis traces Europeanization in two cases – Finland and Norway. Both cases, on the one hand, have similar features of belonging to the Nordic states. On the other hand, they have different experiences of European integration. Process tracing and analytical narratives are the tools used in this research. The empirical research conducted in the Thesis discovered interconnections between European and domestic youth policies: consequences of policy changes, parallels in youth policy agendas. However, in both cases domestic youth policies have specific priorities. European integration has had different impact in the case of Norway and in the case of Finland. These differences seem to be caused by Europeanization and, in Finland, by EU-ization. Despite the fact that the youth dimension is young and not on the top list of European policies, European states introduce changes at domestic levels. This research shows how Europeanization and EU-ization appear in youth policy. It means that in order to design a more effective European youth policy, policy makers should identify which common recommendations and strategies are relevant for each particular state. Further unification of youth policy standards at the European level may cause domestic changes which are not objectively required, and thus would appear only under the “goodness of fit” notion. Instead, it might be more efficient to diversify the youth policy agenda and leave more initiative for domestic youth policies

Interaction of Biliverdin Chromophore with Near-Infrared Fluorescent Protein BphP1-FP Engineered from Bacterial Phytochrome

Near-infrared (NIR) fluorescent proteins (FPs) designed from PAS (Per-ARNT-Sim repeats) and GAF (cGMP phosphodiesterase/adenylate cyclase/FhlA transcriptional activator) domains of bacterial phytochromes covalently bind biliverdin (BV) chromophore via one or two Cys residues. We studied BV interaction with a series of NIR FP variants derived from the recently reported BphP1-FP protein. The latter was engineered from a bacterial phytochrome RpBphP1, and has two reactive Cys residues (Cys15 in the PAS domain and Cys256 in the GAF domain), whereas its mutants contain single Cys residues either in the PAS domain or in the GAF domain, or no Cys residues. We characterized BphP1-FP and its mutants biochemically and spectroscopically in the absence and in the presence of denaturant. We found that all BphP1-FP variants are monomers. We revealed that spectral properties of the BphP1-FP variants containing either Cys15 or Cys256, or both, are determined by the covalently bound BV chromophore only. Consequently, this suggests an involvement of the inter-monomeric allosteric effects in the BV interaction with monomers in dimeric NIR FPs, such as iRFPs. Likely, insertion of the Cys15 residue, in addition to the Cys256 residue, in dimeric NIR FPs influences BV binding by promoting the BV chromophore covalent cross-linking to both PAS and GAF domains.Peer reviewe

Allosteric effects of chromophore interaction with dimeric near-infrared fluorescent proteins engineered from bacterial phytochromes

Fluorescent proteins (FPs) engineered from bacterial phytochromes attract attention as probes for in vivo imaging due to their near-infrared (NIR) spectra and use of available in mammalian cells biliverdin (BV) as chromophore. We studied spectral properties of the iRFP670, iRFP682 and iRFP713 proteins and their mutants having Cys residues able to bind BV either in both PAS (Cys15) and GAF (Cys256) domains, in one of these domains, or without these Cys residues. We show that the absorption and fluorescence spectra and the chromophore binding depend on the location of the Cys residues. Compared with NIR FPs in which BV covalently binds to Cys15 or those that incorporate BV noncovalently, the proteins with BV covalently bound to Cys256 have blue-shifted spectra and higher quantum yield. In dimeric NIR FPs without Cys15, the covalent binding of BV to Cys256 in one monomer allosterically inhibits the covalent binding of BV to the other monomer, whereas the presence of Cys15 allosterically promotes BV binding to Cys256 in both monomers. The NIR FPs with both Cys residues have the narrowest blue-shifted spectra and the highest quantum yield. Our analysis resulted in the iRFP713/Val256Cys protein with the highest brightness in mammalian cells among available NIR FPs.Peer reviewe

Left Ventricular Diastolic Dysfunction Screening by a Smartphone-Case Based on Single Lead ECG.

Aims To investigate the potential of a signal processed by smartphone-case based on single lead electrocardiogram (ECG) for left ventricular diastolic dysfunction (LVDD) determination as a screening method. Methods and Results We included 446 subjects for sample learning and 259 patients for sample test aged 39 to 74 years for testing with 2D-echocardiography, tissue Doppler imaging and ECG using a smartphone-case based single lead ECG monitor for the assessment of LVDD. Spectral analysis of ECG signals (spECG) has been used in combination with advanced signal processing and artificial intelligence methods. Wavelengths slope, time intervals between waves, amplitudes at different points of the ECG complexes, energy of the ECG signal and asymmetry indices were analyzed. The QTc interval indicated significant diastolic dysfunction with a sensitivity of 78% and a specificity of 65%, a Tpeak parameter >590 ms with 63% and 58%, a T value off >695 ms with 63% and 74%, and QRSfi > 674 ms with 74% and 57%, respectively. A combination of the threshold values from all 4 parameters increased sensitivity to 86% and specificity to 70%, respectively (OR 11.7 [2.7-50.9], P < .001). Algorithm approbation have shown: Sensitivity-95.6%, Specificity-97.7%, Diagnostic accuracy-96.5% and Repeatability-98.8%. Conclusion Our results indicate a great potential of a smartphone-case based on single lead ECG as novel screening tool for LVDD if spECG is used in combination with advanced signal processing and machine learning technologies

WATER-SOLUBLE POLYMERIC IONIC 5-FLUOROURACIL COMPLEX BASED ON METHACRYLIC ACID COPOLYMERS

Objective: The objective of this work was to obtain a water-soluble 5-fluorouracil (5-FU) polymeric complex on the basis of a methacrylic acid (MAA) copolymer to be used as an injectable chemotherapeutic agent. Methods: A polymeric carrier was synthesized using tert-butyl methacrylate (TBMA) as a monomer, thioglycolic acid, and azobisisobutyronitrile as a radical polymerization initiator. The polymer was converted by acid hydrolysis into a water-soluble copolymer of TBMA and MAA of 20: 80 mass%, respectively. The copolymer of TBMA and MAA was modified with 5-FU. Their formation was proved using IR and UV spectroscopy. The particle size of the 5-FU polymeric complex was estimated by turbidimetry, which is based on measuring the intensity of light transmitted through a disperse system. The release of 5-FU from the obtained ionic complexes by dialysis in vitro was evaluated. Results: Polymeric carriers were obtained with different amounts of 5-FU (5, 15, 25, 50 mol%). A high peak at λ = 266 nm was observed in the UV spectrum of the polymeric carrier (characteristic of 5-FU). The particle size was estimated at 13 nm for the complex with 5 mol% 5-FU and 26.8 n for the complex with 50 mol% 5-FU. The 5-FU release was estimated in two parallel experiments at 37 °C. One utilized a phosphate-citrate buffer with pH 5.0 to model the intracellular space and the other, a phosphate buffer with pH 7.4 to model the intravascular space. Two systems, with 5 and 15 mol% 5-FU, were chosen for testing. In both phosphate buffer and phosphate-citrate buffer, 5-FU was released from the polymeric complex with 5 mol% 5-FU approximately 1.3 times faster than from the complex containing 5 mol% 5-fluorouracil. The kinetics of 5-FU release from the polymeric complex (5 mol% 5-fluorouracil) showed that the 5-FU release was 77.9% in phosphate-citrate buffer and 59.6% in phosphate buffer over 52 h of dialysis. When the 5-FU release kinetics was studied with the polymeric complex containing 15 mol% 5-FU, the 5-FU release was 100.0% in phosphate-citrate buffer and 75.1% in phosphate buffer over 57 h of dialysis. Conclusion: Water-soluble nanoscale complexes of 5-FU with TBMA–MAA copolymers extend application of 5-FU, while its general toxicity might be lower. The complexes are sufficiently stable at pH 7.4 and readily release 5-FU at pH 5.0

Multiparametric optical bioimaging reveals the fate of epoxy crosslinked biomeshes in the mouse subcutaneous implantation model

Biomeshes based on decellularized bovine pericardium (DBP) are widely used in reconstructive surgery due to their wide availability and the attractive biomechanical properties. However, their efficacy in clinical applications is often affected by the uncontrolled immunogenicity and proteolytic degradation. To address this issue, we present here in vivo multiparametric imaging analysis of epoxy crosslinked DBPs to reveal their fate after implantation. We first analyzed the structure of the crosslinked DBP using scanning electron microscopy and evaluated proteolytic stability and cytotoxicity. Next, using combination of fluorescence and hypoxia imaging, X-ray computed microtomography and histology techniques we studied the fate of DBPs after subcutaneous implantation in animals. Our approach revealed high resistance to biodegradation, gradual remodeling of a surrounding tissue forming the connective tissue capsule and calcification of crosslinked DBPs. These changes were concomitant to the development of hypoxia in the samples within 3 weeks after implantation and subsequent induction of angiogenesis and vascularization. Collectively, presented approach provides new insights on the transplantation of the epoxy crosslinked biomeshes, the risks associated with its applications in soft-tissue reconstruction and can be transferred to studies of other types of implants