Orientational Correlation Research Articles

Multistep Micellization of Standard Surfactants Evidenced by Second Harmonic Scattering.

Processes involving in solution a reduced number of molecules are difficult to identify and characterize. Here, we show that micellization of standard surfactants, namely sodium dodecyl sulfate and trimethyl tetradecyl ammonium bromide, two nonefficient compounds for quadratic nonlinear optics, can be investigated by second harmonic scattering (SHS). In particular, the formation of aggregates at concentrations smaller than the critical micellar concentration is evidenced through a nonmonotonic behavior of the SHS intensity as a function of the surfactant concentration. A simple model based on chemical equilibria between monomers and micelles is proposed to account for the experimental observations. Signature of long-range molecular orientation correlation is revealed by polarization resolved experiments and is discussed regarding micellization and charge-induced effects.

On the orientational correlations in the supercooled chloride lithium aqueous solution using the hybrid reverse Monte Carlo simulation

Employing the Hybrid Reverse Monte Carlo (HRMC) simulation, we compute, using the obtained three-dimensional configurations, the orientational correlations of water molecules in the supercooled 9.26 molal LiCl aqueous solution. This study aims to add relevant structural properties to those obtained in our latest studies and further support our findings. The Li/Cl pair ions hydration shells and the water molecules distribution studied using the Radial Pair Distribution Functions (RPDF), ([Formula: see text]) and ([Formula: see text]) are further described using the Orientational Pair Correlation Functions (OPCF), [Formula: see text] which describes the probability of a water molecule oriented by the Euler angles [Formula: see text], being located at the position [Formula: see text], with respect to another water molecule oriented [Formula: see text] placed at the origin. The high dimensionality of the orientational correlation functions has not presented a calculation disability, as known with several simulations, in the face of the efficiency of the HRMC and the water–water orientational correlation functions showed the dominant impact of ions on the water molecular dipole orientations within the hydration shells and in the hydrogen bonded molecules network.

NaCl increases the dielectric constant of nanoconfined water in phospholipid multilamellar vesicle by enhancing intermolecular orientation correlation rather than rotational freedom of individual molecules

We investigate how the NaCl affects the dielectric constant of nanoconfined water in phospholipid multilamellar vesicles using dielectric relaxation spectroscopy. An anomalous increase in the dielectric constant is observed near the physiological NaCl concentration (0<c<0.3M), which has been consistently proposed in molecular dynamic simulations but is first confirmed by experiment. NaCl accelerates the reorientation motion of surface-bound water, which implies an increase of the rotational degree of freedom. However, for water beyond the hydration layer, retarded collective reorientation motion and increased dielectric strength are observed, suggesting NaCl enhances intermolecular orientation correlation rather than rotational freedom.

Study of Segregation in Non-Dilute Solutions of Linear Diblock Copolymers and Symmetric Miktoarm (or Janus Star) Polymers Using Monte Carlo Simulations with the Bond Fluctuation Model

The bond fluctuation model was employed to characterize the approach to the mesophase separation transition of pure linear AB copolymers and symmetric miktoarms, also called Janus, star polymers, Af/2Bf/2, where f = 6 or 12 is the total number of arms, in a common good solvent. We consider a concentration sufficiently high to mimic the melting behavior and also a lower concentration. The segregation between A and B units is represented by a repulsive interaction parameter, ε. Different total numbers of units are also considered. Results for different properties, such as the molecular size, the asphericity and orientational correlation of blocks, or arms, of different compositions are obtained as a function of the segregation parameter. We also calculate scattering structure factors. The initial effect of segregation on the scattering with opposite contrast factors between the A and B blocks can be explained with a common description based on the random phase approximation for both the linear copolymers and the f = 6 miktoarms, once the numerical form factors of the different molecules in their particular systems are considered. However, the results for f = 12 clearly deviate from this description probably due to some degree of ordering in the position of highly armed molecules.

A generalized scheme for characterizing orientational correlations in condensed phases of high symmetry molecules: SF6 and C60

The orientational correlation scheme introduced earlier for tetrahedral molecules is extended for being able to classify orientational correlations between pairs of high symmetry molecules. While in the original algorithm a given orientation of a pair of tetrahedral molecules is characterized unambiguously by the number of ligand atoms that can be found between two planes that contain each centre and perpendicular to the centre-centre connecting line, in the generalized algorithm, the planes are replaced by cones, whose apex angles are set according to the symmetry of each molecule. To demonstrate the applicability of the method, the octahedral-shaped SF6 molecule is studied in a wide range of phases (gaseous, supercritical fluid, liquid and plastic crystalline) using classical molecular dynamics. By analyzing the orientational correlations, a close-contact region in the first coordination shell and a medium-range order behaviour are identified in the non-crystalline phases. While the former is invariant to changes of the density, the latter showed longer-ranged correlations as density is raised. In the plastic crystalline state, fluorine atoms are oriented along the lattice directions with higher probability. To test the method for icosahedral symmetries, the crystalline structures of room temperature C60 is generated by three sets of potentials that produce different local arrangements. The novel analysis provided quantitative result on preferred arrangements.

ENVIRONMENTAL LITERACY AS A FACTOR OF CONSOLIDATION OF UKRAINIAN SOCIETY

Emerging economy based on innovation, technological progress creates new sources of growth, reinterpreted with environmental positions the principles of interaction with the environment.&#x0D; The relationship of social systems with the components of the natural environment is established through complex correlations of different orientation and depth. Therefore, the level of general scientific study of the processes of interaction between state, society and nature form a new integrated interdisciplinary approaches that integrate and form an unconventional device methodological study of this area.&#x0D; Ecological literacy, which is expressed in the development, justification, and most importantly the practical implementation of optimal methods of environmental impact, can serve as an indicator of social maturity, which determines the nature of personal participation in the process of man-made impact on the environment.&#x0D; In the long term ecological literacy must become an integral part of literacy work and find a real reflection of a system of criteria for socio-economic evaluation of production results as every labor collective and the individual.&#x0D; In modern conditions, the most important trend in business development is socialization, which means: first, active involvement in solving priority social problems of enterprise development, the region and the state as a whole; secondly, clearly defined socially oriented investments of enterprises in the improvement of the internal and external environment, in corporate social programs; third, various forms of charitable and sponsorship activities.&#x0D; Response to environmental risks must become conscious of the need for greening of consciousness and life in Ukraine. That is, learning certain environmental perceptions and attitudes towards nature and implementation in daily practice technologies that do not cause irreparable damage to the environment, changing lifestyles of people to safer spread respect for natural resources.&#x0D; The solution to all these issues requires a thorough environmental legal framework will be to: broad international cooperation in the environmental field to address environmental safety and environmental protection; ensuring social and environmental security; monitoring the problems of ecologically oriented lifestyle in Ukraine according to the method of "Green Barometer" (the Green Barometer); the introduction of new technologies in Ukraine; the need to develop principles for the transition from economics to energy economics.

Topological transformations in hyperuniform pentagonal two-dimensional materials induced by Stone-Wales defects

We discover two distinct topological pathways through which the pentagonal Cairo tiling (P5), a structural model for single-layer $AB_2$ pyrite materials, respectively transforms into a crystalline rhombus-hexagon (C46) tiling and random rhombus-pentagon-hexagon (R456) tilings, by continuously introducing the Stone-Wales (SW) topological defects. We find these topological transformations are controlled by the orientation correlations among neighboring $B$-$B$ bonds, and exhibit a phenomenological analogy of the (anti)ferromagnetic to paramagnetic transition in two-state Ising systems. Unlike the SW defects in hexagonal 2D materials such as graphene, which cause distortions, the defects in pentagonal 2D materials preserve the shape and symmetry of the fundamental cell of P5 tiling and are associated with a minimal energy cost, making the intermediate R456 tilings realizable metastable states at room temperature. Moreover, the intermediate structures along the two pathways are neither crystals nor quasicrystals, and yet these random tilings preserve hyperuniformity of the P5 or C46 crystal (i.e., the infinite-wavelength normalized density fluctuations are completely suppressed), and can be viewed as 2D analogs of disordered Barlow packings in three dimensions. The resulting 2D materials possess metal-like electronic properties, making them promising candidates for forming Schottky barriers with the semiconducting P5 material.

Correlation of Motivation and Value Orientation of Project Managers

The objective of this paper is to identify the relationship between the dimensions of performance motivation and value preferences of project managers in large companies. To examine the relationship, it was first necessary to find out what the value system of project managers is and what their motivational profile is. The research took the form of a questionnaire survey in large Czech companies, which belong to CZ-NACE C. Standardized questionnaires were used for data collection. The PVQ questionnaire was used to determine the value system and the LMI questionnaire was used to determine the motivational profile. Data were evaluated by using descriptive statistics and relationships were evaluated by using Person's correlation coefficient. Student's t-test was used to verify statistical significance. It was found that the analyzed values in the set of respondents are almost the same, all analyzed values are perceived by the respondents as significant. The most represented value among the respondents is benevolence and the least represented is tradition. We identified identical findings in the case of analysis of performance motivation. Of the four dimensions of motivation examined, the project managers addressed confidence in success to be the most important. A statistically significant relationship was found between commitment and power and success, between flexibility and stimulation, universalism and benevolence, between self-control and power, success, conformity and safety, and between confidence in success and power, success and stimulation. Doi: 10.28991/esj-2021-01282 Full Text: PDF

Diffusion of active particles with angular velocity reversal.

Biological and synthetic microswimmers display a wide range of swimming trajectories depending on driving forces and torques. In this paper we consider a simple overdamped model of self-propelled particles with a constant self-propulsion speed but an angular velocity that varies in time. Specifically, we consider the case of both deterministic and stochastic angular velocity reversals, mimicking several synthetic active matter systems, such as propelled droplets. The orientational correlation function and effective diffusivity is studied using Langevin dynamics simulations and perturbative methods.

Comparison of the multi-layer multi-configuration time-dependent Hartree (ML-MCTDH) method and the density matrix renormalization group (DMRG) for ground state properties of linear rotor chains.

We demonstrate the applicability of the Multi-Layer Multi-Configuration Time-Dependent Hartree (ML-MCTDH) method to the problem of computing ground states of one-dimensional chains of linear rotors with dipolar interactions. Specifically, we successfully obtain energies, entanglement entropies, and orientational correlations that are in agreement with the Density Matrix Renormalization Group (DMRG), which has been previously used for this system. We find that the entropies calculated by ML-MCTDH for larger system sizes contain nonmonotonicity, as expected in the vicinity of a second-order quantum phase transition between ordered and disordered rotor states. We observe that this effect remains when all couplings besides nearest-neighbor are omitted from the Hamiltonian, which suggests that it is not sensitive to the rate of decay of the interactions. In contrast to DMRG, which is tailored to the one-dimensional case, ML-MCTDH (as implemented in the Heidelberg MCTDH package) requires more computational time and memory, although the requirements are still within reach of commodity hardware. The numerical convergence and computational demand of two practical implementations of ML-MCTDH and DMRG are presented in detail for various combinations of system parameters.

Elastic moduli of body-centered cubic lattice near rigidity percolation threshold: Finite-size effects and evidence for first-order phase transition.

Extensive numerical simulations of rigidity percolation with only central forces in large three-dimensional lattices have indicated that many of their topological properties undergo a first-order phase transition at the rigidity percolation threshold p_{ce}. In contrast with such properties, past numerical calculations of the elastic moduli of the same lattices had provided evidence for a second-order phase transition. In this paper we present the results of extensive simulation of rigidity percolation in large body-centered cubic (bcc) lattices, and show that as the linear size L of the lattice increases, the elastic moduli close to p_{ce} decrease in a stepwise, discontinuous manner, a feature that is absent in lattices with L<30. The number and size of such steps increase with L. As p_{ce} is approached, long-range, nondecaying orientational correlations are built up, giving rise to compact, nonfractal clusters. As a result, we find that the backbone of the lattice at p_{ce} is compact with a fractal dimension D_{bb}≈3. The absence of fractal, scale-invariant clusters, the hallmark of second-order phase transitions, together with the stairwise behavior of the elastic moduli, provide strong evidence that, at least in bcc lattices, many of the topological properties of rigidity percolation as well as its elastic moduli may undergo a first-order phase transition at p_{ce}. In relatively small lattices, however, the boundary effects interfere with the nonlocal nature of the rigidity percolation. As a result, only when such effects diminish in large lattices does the true nature of the phase transition emerge.

CORRELATIONS OF MOTIVATIONAL-MEANING ORIENTATIONS AND PERSONAL FACTORS FOR PATIENTS WITH DIABETES MELLITUS

The article studies correlations between motivational-meaning orientations and personal factors for patients having diabetes mellitus. The study involved 79 people undergoing treatment for diabetes mellitus at the Kiev City Endocrinology Center: 31 men, 48women, with average age of 52.22, σ = 16.61. The following methods were used: “Diagnostics of the motivational structure of personality” (Milman, 1990), “Meaningful life orientations” (Leontiev, 2000) and “Five-Factor Personality Questionnaire” (Khromov, 2000). The motives of support were significantly more important than the motives of development for patients with diabetes mellitus, which indicated the regressive personal tendencies. As for meaningful life orientations, the indicator of goals was low, the indicators of satisfaction with a life process and life results were somewhat more optimistic. The results for the indicators of the locus of control-Self and the locus of control-life were different: locus of control-Self was low, but locus of control-life was sufficient. That is, the respondents believed in the fundamental capability to manage their lives, but they did not believe that they were able to manage it themselves. The obtained data are consistent with the results of other authors on the externality of the locus of control for such patients. Men with diabetes mellitus more often, in comparison with women, see life meaning in its results, feel themselves masters of their own lives, and are guided in their behavior by motives of life support. As for the analyzed personal traits, low values were obtained for all factors identified with the Five-Factor Personality Questionnaire. “Playfulness-practicality” factor turned up to be the lowest, which reflected that the studied people had tendency to be closed to new experience, afraid for changes but to be more practical, realistic, focus on adaptation to everyday life, and be concern about the material side of life. The revealed correlations of motivational-meaning orientations with personal traits for patients with diabetes mellitus were weak and of a low significance, therefore, they rather allow us to speak about tendencies than about regularities. These tendencies, first of all, include the specific refraction of motivational-meaning orientations through the respondents’ personal traits changed because disease, namely, egocentrism, a low prosocial orientation, the external locus of control, rejection of new experience, suspiciousness, misunderstanding of other people and focusing on one’s own problems.

Magnetic anisotropic colloids in nematic liquid crystals: Fluctuating dynamics simulated by multi-particle collision dynamics

Elongated colloids with a permanent magnetic moment and immersed in a nematic liquid crystal are studied numerically using a mesoscopic scheme that supports fluctuations, hydrodynamics, and topological defects. Colloids are accompanied by disclinations curves and subjected to an effective torque caused by the nematic environment and to a magnetic torque due to an external magnetic field. The case is analyzed where these torques compete to bring colloids to two different mutually perpendicular equilibrium states. The fluctuating dynamics of the colloid-defect pair is studied in terms of orientational correlation functions. Analytical expressions for these correlations are derived on the basis of an approximated planar lineal model. A good agreement is found between the numerical and analytical methods when magnetic torques are much larger than nematic torques, while for smaller magnetic torques nonlinear effects are demonstrated to be important. As conclusion, the numerical technique could be considered a reliable approach to the rotational motion of polar nanoparticles in liquid crystals.

Orientational Pair Correlations and Local Structure of Benzonitrile from Molecular Dynamics Simulations with Comparisons to Experiments.

We present an experimentally parametrized molecular dynamics study of single-molecule and collective orientational relaxation in neat benzonitrile through the analysis of the reorientational anisotropy and polarizability anisotropy time correlation function (PA-TCF). The simulations show that the PA-TCF is dominated by collective reorientation after 20 ps. Collective reorientation is found to be slower than single-molecule reorientation by a factor of 1.67, consistent with recent experiments. The simulations provide direct evidence of local antiparallel benzonitrile configurations. These structures, which have been the center of some debate, are responsible for the slower rate of collective versus single-molecule reorientation in the liquid. Further structural analysis indicates that significant Coulombic interactions between the nitrile group and hydrogen atoms on adjacent molecules play a role in the formation of the antiparallel structures. The single-molecule dynamics reflected in the anisotropy are complex and consist of a ballistic regime, restricted angular diffusion, and spatially anisotropic free diffusion. The principal components of the rotational diffusion tensor are independently obtained and shown to reproduce the free diffusion regime of the anisotropy for each principal axis according to the predictions of a previous theory.

Cross‐sex shifts in two brain imaging phenotypes and their relation to polygenic scores for same‐sex sexual behavior: A study of 18,645 individuals from the UK Biobank

Genetic and hormonal factors have been suggested to influence human sexual orientation. Previous studied proposed brain differences related to sexual orientation and that these follow cross‐sex shifted patterns. However, the neurobiological correlates of sexual orientation and how genetic factors relate to brain structural variation remains largely unexplored. Using the largest neuroimaging‐genetics dataset available on same‐sex sexual behavior (SSB) (n = 18,645), we employed a data‐driven multivariate classification algorithm (PLS) on magnetic resonance imaging data from two imaging modalities to extract brain covariance patterns related to sex. Through analyses of latent variables, we tested for SSB‐related cross‐sex shifts in such patterns. Using genotype data, polygenic scores reflecting the genetic predisposition for SSB were computed and tested for associations with neuroimaging outcomes. Patterns important for classifying between males and females were less pronounced in non‐heterosexuals. Predominantly in non‐heterosexual females, multivariate brain patterns as represented by latent variables were shifted toward the opposite sex. Complementary univariate analyses revealed region specific SSB‐related differences in both males and females. Polygenic scores for SSB were associated with volume of lateral occipital and temporo‐occipital cortices. The present large‐scale study demonstrates multivariate neuroanatomical correlates of SSB, and tentatively suggests that genetic factors related to SSB may contribute to structural variation in certain brain structures. These findings support a neurobiological basis to the differences in human sexuality.

Wear behavior of extruded ZK60 magnesium alloy in simulated body fluid with different pH values

Two specimens were prepared along the extrusion (ED) and transverse (TD) directions of the extruded ZK60 magnesium alloy bar, respectively. The wear behavior of ED and TD specimens in air (Dry) and simulated body fluid (SBF) of different pH values (pH 4, 7.4 and 9) was evaluated using ball-on-disk configuration. The wear morphology of specimens was characterized by three-dimensional white light interference profiler, scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The results indicated that pH value had a significant effect on the wear behavior of specimens. The average friction coefficient of ED and TD specimens in each environment decreased in the following order: pH 7.4 ≈ pH 9 > Dry > pH 4, and the wear volume decreased in the following order: Dry > pH 4 > pH 7.4 ≈ pH 9. Abrasive wear and oxidative wear were the main wear mechanisms of ED and TD specimens in air, and corrosive wear was taken place in SBF of pH 4, 7.4 and 9. The formation of Mg(OH)2 film improved the wear resistance of specimen in SBF. The wear behavior of ED and TD specimens in SBF of pH 4 showed an orientation correlation, and the wear volume of TD specimen was greater than that of ED specimen. The effect of pH value and initial texture on the wear behavior of magnesium alloy was discussed.

Correlation of grain orientations and the thickness of gradient MoS2 films.

In this study, we synthesized gradient MoS2 films with a home-made suspended mask and characterized them by transmission electron microscopy (TEM) and Raman spectroscopy. The advantage of using gradient films is to simultaneously produce numerous samples under the same growth condition but with different thicknesses. The cross-sectional TEM images and their Fourier transform spectra revealed the thickness dependency of the grain orientations for synthetic MoS2 films. Combining the TEM results and the data of Raman A1g and E12g peaks, we found the correlation between the grain orientation and the A1g/E12g peak area ratio. We demonstrated the potential of using the non-polarized Raman Spectroscopy to characterize the grain structures of synthetic MoS2 films.

Analysis of the motivational features of the choice of the teaching profession by students

The relevance of the present study is determined by the demand of the state and society for training pedagogical personnel who are highly motivated for professional activity and chose their profession consciously. Thus, the first premise of the conducted study lies in the need to improve the quality of pedagogical training in the Moscow metropolis. The second premise is the need for the scientific study of the structure of personality and the interrelation of its components presented by personal values and the motives behind the choice of profession. The study aims to identify the correlation of personal value orientations and motives for choosing a future profession in students of the pedagogical faculty of the Moscow City University. The study methods include projective methods (a survey and essays) and standardized methods (Rokeach’s Personal Values Survey, Schwartz’s Value Survey, and “Test of life-meaning orientations” by D.A. Leontiev). The study confirms that personal values correlate with the motives for the choice of profession in pedagogical faculty students. A high correlation between the motive behind choosing the teaching profession and personal values is found in the orientation on interaction with people and on oneself, awareness of one’s professional choice, and social and cultural conditioning. In the categories of gender and financial status, the motives for choosing a profession do not correlate with students’ personal values. The novelty of the study lies in the identification and empirical verification of the scientific method for determining students’ involvement in the future teaching profession. The significance of the study is found in the fact that it reveals a new technology for vocational guidance of applicants of pedagogical university training programs. Moreover, implementation of the study results may increase the effectiveness of the design of students’ education in improving their professional motivation. The presented research makes a scientific contribution to the study of a person’s activity and independence in self-realization in life, the freedom of choice and responsibility for it, for one’s decisions and actions, as well as in the study of the values of future teachers.

Explaining Risk Perception of Climate Change in Indonesia through Cultural Dimension of Uncertainty Avoidance, Collectivistic, and Long-term Orientation

Risk perception of climate change is believed to be the first step to tackle climate change problems around the world. There are many factors to cause people being aware of climate change risks but research on cultural dimensions is rarely conducted. This research examines the correlation of cultural dimension uncertainty avoidance, collectivistic, and long-term orientation with risk perception of climate change. The research was conducted in Indonesia as the country with the high score in uncertainty avoidance, collectivistic, and long-term orientation. Data was collected using online survey and shared in several cities in Indonesia, in three largest Islands, Sumatera, Java, and Sulawesi. It was found that risk perception of climate change is positively correlated to the cultural dimensions of uncertainty avoidance, collectivistic, and long-term orientation. Demography variables such as age, gender, education level and disaster experiences have found not related to the risk perception of climate change. The result enriches the contribution of cultural dimensions in shaping risk perception especially risk perception of climate change, and the description of Indonesia’s cultural dimensions and risk perception of climate change.

Self-Supervised Learning Across Domains.

Human adaptability relies crucially on learning and merging knowledge from both supervised and unsupervised tasks: the parents point out few important concepts, but then the children fill in the gaps on their own. This is particularly effective, because supervised learning can never be exhaustive and thus learning autonomously allows to discover invariances and regularities that help to generalize. In this paper we propose to apply a similar approach to the problem of object recognition across domains: our model learns the semantic labels in a supervised fashion, and broadens its understanding of the data by learning from self-supervised signals on the same images. This secondary task helps the network to focus on object shapes, learning concepts like spatial orientation and part correlation, while acting as a regularizer for the classification task over multiple visual domains. Extensive experiments confirm our intuition and show that our multi-task method, combining supervised and self-supervised knowledge, provides competitive results with respect to more complex domain generalization and adaptation solutions. It also proves its potential in the novel and challenging predictive and partial domain adaptation scenarios.