Sharp Stratification Research Articles

ВЛИЯНИЕ СОЦИО-ЭКОНОМИЧЕСКИХ И КУЛЬТУРНЫХ ФАКТОРОВ НА РОСТ И РАЗВИТИЕ ДЕТЕЙ В ВОЗРАСТЕ ОТ 0 ДО 1 ГОДА В ПАКИСТАНЕ

The weight of newborns in Pakistan is usually kept at the lower limit of the norm (2.5-3 kg), which is associated with both the peculiarities of the constitution of Pakistani women and the peculiarities of their life and nutrition. However, by the age of 1 year, there is a sharp stratification of children in height and weight: children in wealthy families most often suffer from increased weight (and even obesity), children from lower social groups - from malnutrition, both qualitative and quantitative. This phenomenon is associated both with medical problems and the system of organization of medical pediatric care in the country, as well as with socio-economic and cultural factors, such as: the availability of baby food, the culture of baby food, cultural traditions of the region, the level of family education, and others. According to the study, recommendations are made to regulate medical, socio-economic and cultural factors for the optimal development and growth of children in Pakistan.

ORTEGA Y GASSET AND THE QUESTION OF THE BODY

My essay is devoted to the very early and attractive understanding of the lived body in Ortega y Gasset’s thought. I focus especially on the text “Vitality, Soul, Spirit” of 1925, which can be considered a proto-phenomenological approach to the issue of embodiment. Ortega identifies “vitality” with “the intrabody” and makes the latter the founding dimension of subjectivity, at the basis of the affective sphere (“soul”) and at the basis of the intellectual and volitional sphere (“spirit”). In a manner very close to Husserl’s unpublished manuscripts, he also shows how the body is the only reality of which there is simultaneously external perception, as if it were just another thing in the world that everyone else can see, and internal perception, which only the self can have and feel. The study also points out, however, the two major difficulties that I detect in Ortega’s precocious attempt. A first doubt concerns the too sharp stratification of vitality, soul and spirit, as can be seen in the analysis of the experiences of pain and of mobility. A second doubt concerns the ontological hesitations surrounding Ortega’s position, which is torn between a coherent phenomenological perspective and a vitalist position in which my body is only an emanation of the lifestream of the universe.

Social and legal protection of personnel of the security and defense sector of Ukraine in modern conditions

The article examines the main directions of ensuring social and legal protection of the personnel of the security and defense sector of Ukraine in modern conditions. Among such directions, a special place is occupied by the identification and elimination of the causes that lead to the sharp stratification of society during the transition to martial law in the conditions of the market economy; taking timely measures to counter demographic crisis processes; creation of an effective system of social protection of a person, protection and restoration of their physical and spiritual health, etc. Guarantees of social and legal protection have a direct impact on the motivation, morale and fighting capacity of the personnel of the security and defense sector of Ukraine, especially in the conditions of martial law. Legal acts regulating social and legal protection, its state and ways of improvement are analyzed. These problems are considered from the standpoint of social and personnel security, which play an important role in the comprehensive provision of national security of Ukraine. This approach made it possible to correctly identify significant threats and risks in the specified area, to avoid a social and personnel disaster. The characteristics of these new scientific categories, their connection with social and personnel policy in the state are given. The experience of foreign countries of the European Union and the North Atlantic Bloc, gained from the above-mentioned issues, is presented.

Irrational Foundations of Suicide

The article discusses theoretical studies on suicides and suicidal behavior, discusses the features of the development of this phenomenon in different social groups, provides a general typology of studies already conducted through the prism of understanding the impact of social experience (external pressure factors, crisis, stressful situations) and intrapersonal problems (related to personality traits, socialization and adaptation of a person to external influences and internal experiences and processes). The paper also presents the results of a comprehensive study of the irrational foundations of suicide. The first is based on an analysis of the materials of a quantitative survey of Russians (n-1200) conducted in 2022 in all regions of the Russian Federation. The second one is constructed on the interpretation of qualitative data ‒ the analysis of expert interviews (n-18), psychologists, psychotherapists, psychiatrists, philosophers, criminologists. The third is the analysis of articles and publications in social networks devoted to suicides and promoting suicidal behavior (n-1620), which made it possible to identify key semantic lexemes that indicate the main causes and factors in the development of suicidal behavior and suicides. As a result of the study, we identified nine of them: 1) age (17–21, 40–45, 55–65); 2) limitation of emotional and sensory experience; 3) difficulties in building communications due to their own incompetence or limited opportunities; 4) problems of self-determination in society (conflict with a group, forced confrontation ‒ in the family, at work, among friends); 5) weakly expressed own worldview; 6) feeling of loneliness; 7) a sharp stratification of people in terms of the level and quality of life; 8) social inertia and frustration; 9) destructive hobbies (drug addiction, drunkenness). The use of these research methods made it possible to supplement and expand the initial materials and data of the work, to reveal the potential for interaction at the methodological and practical level and to identify several prospects for topics for further scientific research. It is indicated that the quality of life is based on the ability to predict the future, the prevention of suicidal behavior and suicide can become the basis for social stability and social reproduction.

“NEW INEQUALITY” AND ECONOMIC GROWTH AFTER COVID-19

The article analyzes the main forms of manifestation of the "new inequality" caused by the coronavirus crisis. The author identifies the reasons for the growing inequality in developed countries and reveals its tendencies in incomes, benefits and compensations received, in welfare of various decile groups of employees. Among the causes of economic inequality there are: rent-seeking, misguided macroeconomic policy, the declining role of trade unions, the role of new technologies and changes in the structure of labor demand. A new form of economic inequality is revealed: the relationship between the level of health and the level of education (income). A new ruling class of developed countries has been identified that is interested in further strengthening economic inequality. The author shows that the pandemic has led to a sharp stratification of income and the welfare of employees, both within countries and between countries, turning inequality into a dangerous economic disease. According to the author, the most striking manifestation of the "new inequality" on a global scale is the lack of access to vaccinations in most countries of the world. The article shows the negative impact of income inequality on economic growth in the long run. The author believes that the "new inequality" requires a change in national macroeconomic policy after the coronavirus crisis.

Exploring socioeconomic inequalities and access to elite postgraduate education among English graduates

A worldwide trend towards high levels of participation in higher education, paired with concerns about the post-university destinations of an increasing pool of graduates, have brought about two parallel phenomena: a process of sharp stratification in higher education and the growing relevance of postgraduate education as undergraduate study becomes nearly ubiquitous, particularly among the most advantaged groups of students. To date, the literature on socioeconomic inequalities and access to higher education has focussed on undergraduate education, with some researchers specifically investigating access to the most prestigious institutions. We contribute to this body of research by investigating the effects of socioeconomic characteristics on access to postgraduate education at those universities believed to deliver elite forms of higher education. We look at access to ‘elite’ postgraduate education among English graduates, operationalised as belonging to the Russell Group of research-intensive universities. We analyse an exceptionally large dataset (N = 533,885) capturing graduate destinations, including postgraduate education at specific institutions. We find that socioeconomic inequalities in attending an elite postgraduate degree persist, but these are mediated by educational variables. Socioeconomically advantaged students are more likely to attain a good degree and to attend an elite institution at the undergraduate level, which powerfully predicts access to elite postgraduate education.

Retention of rising droplets in density stratification

In this study, we present results from experiments on the retention of single oil droplets rising through a two-layer density stratification. These experiments confirm the significant slowdown observed in past literature of settling and rising particles and droplets in stratification, and are the first experiments to study single liquid droplets as opposed to solid particles. By tracking the motion of the droplets as they rise through a stratified fluid, we identify two timescales which quantitatively describe this slowdown: an entrainment timescale, and a retention timescale. The entrainment timescale is a measure of the time that a droplet spends below its upper-layer terminal velocity and relates to the length of time over which the droplet's rise is affected by entrained dense fluid. The retention time is a measure of the time that the droplet is delayed from reaching an upper threshold far from the density transition. Both timescales are found to depend on the Froude and Reynolds numbers of the system, Fr $=U_u/(Nd)$ and Re $=\rho_u U_u d/\nu$. We find that both timescales are only significantly large for Fr $\lesssim1$, indicating that trapping dynamics in a relatively sharp stratification arise from a balance between drop inertia and buoyancy. Finally, we present a theoretical formulation for the drag enhancement $\Gamma$, the ratio between the maximum stratification force and the corresponding drag force on the droplet, based on a simple force balance at the point of the velocity minimum. Using our experimental data, we find that our formulation compares well with recent theoretical and computational work by Zhang et al. [J. Fluid Mech. 875, 622-656 (2019)] on the drag enhancement on a solid sphere settling in a stratified fluid, and provides the first experimental data supporting their approach.

Медицина Византийской империи: история и философия

It is shown that the history of medicine in the Byzantine Empire is characterized by almost complete stagnation of development throughout the entire thousand years of the empire, for which characteristic was the domination of religious and magical practices represented as astrology, magic, occultism, neoplatonism over scientific ones, extremely low levels of education and training of doctors. The article points out that one of the leading causes of stagnation of the development of medical science in the Byzantine Empire was the formation of the civil church, which was completely controlled, both in administrative and doctrinal terms, by imperial government, which led to the secularization of the church and its transformation in a great feudal lord; to introduction of pagan beliefs and provisions to the church; to formation and prosperity of superstitions and rituals characteristic of paganism. It is shown that the state subjugating church lost its necessary spiritual foundation (without which it is impossible to build a healthy and prosperous society) resulting in the formation of extremely backward socio-economic situation of Byzantium, with long persistence of slave relations, pervasive embezzlement, huge bureaucracy, corrupt executive system, sharp stratification of society, low level of science in general and medicine in particular.

Sources, quality and transfers of organic matter in a highly-stratified sub-Arctic coastal system (Saint-Pierre-et-Miquelon, NW Atlantic)

In response to ongoing global climate change, marine ecosystems in the northwest Atlantic are experiencing one of the most drastic increases in sea surface temperatures in the world. This warming can increase water column stratification and decrease surface nutrient concentrations, in turn impacting primary productivity and phytoplankton assemblages. However, the exact impacts of these changes on sources and quality of organic matter as well as its transfers to the benthic compartment remain uncertain. This survey characterized organic matter sources and quality within a highly-stratified sub-Arctic coastal system (Saint-Pierre and Miquelon) and described its transfer towards a biomass-dominant primary consumer, the sand dollar Echinarachnius parma. This study analyzed fatty acid and stable isotope (δ13C and δ15N) composition of surface and bottom Particulate Organic Matter (s-POM and b-POM, respectively), Sedimentary Organic Matter (SOM) and sand dollar tissue along a near shore to offshore gradient during two contrasting seasons associated either with sharp or weak water column stratification (i.e. High vs Low Stratification Periods). Results revealed high relative abundances of polyunsaturated fatty acids (notably macro- and microalgae markers) in POM during the Low Stratification Period while the High Stratification Period was characterized by elevated relative abundance of saturated fatty acids indicating a higher organic matter degradation state. In addition, strong seasonal differences were also observed in food availability with four-fold higher concentrations in total suspended solids during Low vs High Stratification Periods. These results suggested thus multiple negative effects of stratification on pelagic-benthic coupling and POM quality. Lower nutrient repletion of surface waters during period of sharp stratification diminishes pelagic-benthic coupling by reducing food availability, POM quality and vertical transfer of organic matter. By contrast, the sediment-based diet of E. parma showed a low spatiotemporal variability reflecting the homogenous composition of the SOM. This study suggests that intensified water column stratification due to increasing sea surface temperatures may modify the pelagic-benthic coupling and future quality and composition of POM pools.

Normal Mode Decomposition and Dispersive and Nonlinear Mixing in Stratified Fluids

Motivated by the analysis of the propagation of internal waves in a stratified ocean, we consider in this article the incompressible Euler equations with variable density in a flat strip, and we study the evolution of perturbations of the hydrostatic equilibrium corresponding to a stable vertical stratification of the density. We show the local well-posedness of the equations in this configuration and provide a detailed study of their linear approximation. Performing a modal decomposition according to a Sturm–Liouville problem associated with the background stratification, we show that the linear approximation can be described by a series of dispersive perturbations of linear wave equations. When the so-called Brunt–Vaisala frequency is not constant, we show that these equations are coupled, hereby exhibiting a phenomenon of dispersive mixing. We then consider more specifically shallow water configurations (when the horizontal scale is much larger than the depth); under the Boussinesq approximation (i.e., neglecting the density variations in the momentum equation), we provide a well-posedness theorem for which we are able to control the existence time in terms of the relevant physical scales. We can then extend the modal decomposition to the nonlinear case and exhibit a nonlinear mixing of different nature than the dispersive mixing mentioned above. Finally, we discuss some perspectives such as the sharp stratification limit that is expected to converge towards two-fluid systems.

Non-Newtonian effects on solid particles settling in sharp stratification

Gravitational settling of solid particles through density interfaces is studied numerically when at least one of the fluids is non-Newtonian. The Carreau–Yasuda model is used to model the shear-thinning behavior of the non-Newtonian fluid. The coupled level-set and volume-of-fluid method is used to track the interface between the two fluids. It is found that the presence of shear-thinning fluids significantly affects the settling dynamics of solid spheres. For lower power index, the lighter fluid is more entrained by the sphere into the denser fluid. It is revealed that the sphere velocity after impacting the interface increases with the power index, density ratio and buoyancy jump. The shear-thinning effect of the upper and lower non-Newtonian fluids is quite noticeable and the motion of the solid sphere before crossing the interface is different to the case of Newtonian fluids. For the case of upper Newtonian fluid, there is a smaller resistance force at the interface, which causes the sphere to fall in the lower non-Newtonian fluid with about 90% of its terminal velocity.

Динамика социокультурной трансформации села: модели эволюции

The analysis of socio-cultural dynamics of rural local communities development in the conditions of structural transformations in production-economic and institutional activity shows that a new paradigm of rural development is being formed, based on the doctrine of multi-layered economy. Rural communities, representing a socio-territorial location, generate models of maintaining their identity, reflecting the social structure, conditions, lifestyle and standard of living. The socio-cultural behavior of the villagers determines the social and mental mechanisms of development, including the reproduction of the population as a subject of socio-cultural activities. The socio-cultural portrait of rural communities reflects the main problems of their development: differentiation of the level and quality of life of rural local communities, sharp stratification into the rich and very poor.

Estuarine Ecosystems and Their Place in Natural River Mouth Complexes of the Arctic: A Case Study of the Yenisei Mouth Area

The estuarine ecosystem is characterized by the mixing of seawater and freshwater with a resulting salinity of 0.5 to 22–26‰, which is preserved for no less than 2–3 weeks, and by the presence of specific brackish water species. The distinguishing features of Arctic estuarine ecosystems are a sharp thermohaline stratification of the waters and, as a consequence, a difference in the boundaries of the brackish water biota distribution near the bottom and in the pelagic zone. Note that only the bottom estuarine biocenoses are characteristic of the river mouth area. The most important factor in the Arctic estuarine ecosystems is the longitudinal migrations of the halocline, especially seasonal ones. The coincidence of the borders of distribution of the true brackish water species with the borders of hydrological and morphological regions of the Yenisei River estuary defined according to long-term observations is noteworthy. Given the relative similarity of the Arctic estuarine ecosystems in their physical, chemical, and biotic components associated with the latitudinal uniformity of the mouths, we assume the presence of this correlation in other estuarine areas as well. In this case, a single survey of the benthos may give the same result as multiyear series of hydrological observations in the regionalization of an estuarine ecosystem.

Nonlinear hydroelastic waves traveling in a thin elastic plate floating on a two-layer fluid

Effects of the sharp stratification of fluid density on the nonlinear hydroelastic waves traveling in an infinite elastic plate floating on a two-layer inviscid fluid are analytically investigated with the aid of the homotopy analysis method. Under the assumptions that the upper and lower fluid layers with different constant densities are incompressible and the motion is irrotational, the problem is formulated within the frame of the potential flow theory. The convergent series solutions for the velocity potentials, the plate deflection and the interfacial elevation are derived, from which the interaction between surface hydroelastic waves and interfacial gravity waves is studied. The influences of different physical parameters, including the density ratio and the depth ratio of the fluid layers, Young’s modulus and the thickness of the plate on the progressive waves are discussed. It is found that the increment of those plate parameters has slight influence on the interfacial wave elevation and apparently changes the plate deflection. A larger density ratio or depth ratio of the fluid layers can reduce the plate deflection and the interfacial wave elevation.

Assessment of the Black Sea observing system. A focus on 2005-2012 Argo campaigns

An observing system in the Black Sea combining remote sensing data such as sea level anomalies from altimetry, sea surface temperature from satellite radiometer and data from Argo floats has been analyzed with the aim to quantify the contribution of different information sources when reconstructing the ocean state. The main research questions are: (1) do Argo float measurements substantially impact the quality of estimates, (2) what is the dependence of this quality upon the data and sampling used, and (3) are there specific Black Sea issues? Numerical model output and statistical analysis were used for this purpose. It has been demonstrated that the statistical method performs in a consistent way reproducing known geophysical patterns. Maximum footprints of sea level, salinity and temperature were illustrated, most of them clearly connected with specific thermohaline conditions and the general circulation. Reduced analysis capabilities were identified as associated with a low level of dynamical coupling between the shelf and the open ocean, mesoscale dynamics and representation of diapycnic processes in the models. The accuracy of Argo pressure measurements appeared very important to resolve the extremely sharp stratification in the upper layers. The present-day number of Argo floats operating in the Black Sea of about 10, seems optimal for operational purposes.

A model for internal bores in continuous stratification

AbstractWe describe a model for the speed of an internal bore as a function of amplitude in continuous stratification of arbitrary form. The model is developed from the Dubreil-Jacotin–Long theory for nonlinear solitary waves in the conjugate flow limit, which represents an internal hydraulic jump, by allowing dissipation across the jump. The bore speeds predicted by the model are consistent in both the small- and large-amplitude limits with the waveguide intrinsic to the ambient stratification. The model therefore represents a significant advancement over previous theories limited to sharp two-layer stratification. The model shows good agreement with Navier–Stokes simulations of both undular and turbulent internal bores generated by dam break into a continuously stratified ambient with a finite pycnocline, predicting both the front speed as well as the velocity and density structure through the bore. A model is required for the structure of the energy dissipation, and we introduce a one-parameter closure that produces excellent agreement with numerical results, particularly in the parameter limit that maximizes the overall dissipation. By varying the dissipation parameter, the model reproduces previous two-layer theories in the thin-pycnocline limit, and suggests an improved two-layer front speed relationship. It is demonstrated that, even for the sharp two-layer limit, continuous stratification, and particularly the nonlinear waveguide, must be accounted for in order to accurately predict the bore speed and structure.

Determination of Extratropical Tropopause Height in an Idealized Gray Radiation Model

Abstract This paper investigates the mechanisms that determine the extratropical tropopause height, extending previous results with a Newtonian cooling model. A primitive equation model forced by a meridional gradient of incoming solar radiation, with the outgoing infrared radiation calculated using a simple gray radiation scheme, is now used. The tropopause is defined as the top of the boundary layer over which dynamical heat transport moves the temperature away from radiative equilibrium, and its height is estimated from the isentropic mass flux. Depending on parameters, this tropopause may or may not be associated with a sharp stratification change, and it may or may not be possible to define a thermal tropopause. The mass flux and thermal tropopause display similar sensitivity to external parameters when the latter can be defined; this is a sensitivity in good agreement with predictions by a radiative constraint. In some contrast to the Newtonian model, the radiative constraint is now quite effective in preventing adjustment to marginal criticality with realistic parameters. The meridional structure of the thermal tropopause displays a jump in height at the jet latitude, which appears to be due to the formation of a mixing barrier at the jet maximum when baroclinicity has a finite vertical scale. As meridional potential vorticity mixing is inhibited across the jet, a discontinuity is created between weakly stratified air on its warm side and strongly stratified air on its cool side. The meridional stratification contrast is created by adiabatic cooling and warming by the residual circulation, as this circulation must be deflected vertically to avoid the mixing barrier at the jet maximum.

Drops settling in sharp stratification with and without Marangoni effects

We present numerical simulations of drops settling in a layered ambient fluid. We focus on nearly spherical drops with Reynolds numbers of order 10. The ambient is composed of miscible fluids, with the top layer lighter than the lower one, representing fluid stratified through temperature or salinity variations, while the drop itself is heavier than both layers. The surface tension between the ambient and the drop may or may not be different for each layer. Such a system can be used to model oil droplets settling or rising in the ocean. When surface tension is uniform, the drop slows down significantly as it encounters the transition region, due to entrained fluid from the upper layer, before accelerating again in the lower layer. We characterize this effect in terms of the sharpness of the transition, and the drop's Reynolds number. When the upper and lower surface tensions are not matched, the drop may either suddenly accelerate through the transition region if the lower surface tension is less than the upper one, or be prevented from crossing into the lower layer if the lower surface tension is larger than the upper one. We focus on the drop's speed across the transition, and determine the conditions under which a drop may remain suspended at the transition region.

Pastoral Communities in the Sardinian Highlands (Italy): A View on Social Mobility

For several decades the socio-economic and political organization of rural communities in the northern Mediterranean has been a central topic of ethnographic and modern historical research. Although the concept of (rural) class has generally been avoided, a scholarly picture has often been maintained of a sharp social stratification in local contexts. In this framework the notions of peasantry and patronage have frequently been applied. This article argues that on occasion rural communities in southern Europe showed a rather flexible social stratification and high amounts of social mobility in particular among shepherd groups. The case study is of the agro-pastoral community of Fonni in the central mountains of Sardinia (Italy), which has been characterized predominantly by a pastoral economy based on sheep and goat herding during the nineteenth and twentieth centuries.

It is not merely about life on the screen: urban Chinese youth and the Internet café

The Internet café (wangba) continues to enjoy high popularity among urban Chinese youth, mostly members of China's only-child generation, despite the derogatory connotations the wangba carries, official control and widely diffused access at home. Based on observation at wangbas and in-depth interviews with urban youth, I explore from the Internet café goers’ perspective what wangba going is all about. The study shows that the wangba serves as a heterotopian third place for the goers. They are there, often against the will of various authorities, for a sense of freedom, relaxation, community, and equality as well as fun, which can hardly be found elsewhere in their lives. The meanings they assign to the wangba are closely related to their social-biographical situations as urban only children typically under great parental expectations in a society characterised by sharp social stratification, fierce competition, lack of security, consumerism, corruption and unfairness in the distribution of resources. In this sense, the wangba is seen as a necessary space for existential reasons, in sharp contrast to the negative portrayal of the wangba as a mere den of iniquity in both official and popular discourses.