Dynamic Heterogeneity in Ring-Linear Polymer Blends

We present results from a direct statistical analysis of long molecular dynamics (MD) trajectories for the orientational relaxation of individual ring molecules in blends with equivalent linear chains. Our analysis reveals a very broad distribution of ring relaxation times whose width increases with increasing ring/linear molecular length and increasing concentration of the blend in linear chains. Dynamic heterogeneity is also observed in the pure ring melts but to a lesser extent. The enhanced degree of dynamic heterogeneity in the blends arises from the substantial increase in the intrinsic timescales of a large subpopulation of ring molecules due to their involvement in strong threading events with a certain population of the linear chains present in the blend. Our analysis suggests that the relaxation dynamics of the rings are controlled by the different states of their threading by linear chains. Unthreaded or singly-threaded rings exhibit terminal relaxation very similar to that in their own melt, but multiply-threaded rings relax much slower due to the long lifetimes of the corresponding topological interactions. By further analyzing the MD data for ring molecule terminal relaxation in terms of the sum of simple exponential functions we have been able to quantify the characteristic relaxation times of the corresponding mechanisms contributing to ring relaxation both in their pure melts and in the blends, and their relative importance. The extra contribution due to ring-linear threadings in the blends becomes immediately apparent through such an analysis

A hybrid kinetic Monte Carlo method for simulating silicon films grown by plasma-enhanced chemical vapor deposition

We present a powerful kinetic Monte Carlo (KMC) algorithm that allows one to simulate the growth of nanocrystalline silicon by plasma enhanced chemical vapor deposition (PECVD) for film thicknesses as large as several hundreds of monolayers. Our method combines a standard n-fold KMC algorithm with an efficient Markovian random walk scheme accounting for the surface diffusive processes of the species involved in PECVD. These processes are extremely fast compared to chemical reactions, thus in a brute application of the KMC method more than 99% of the computational time is spent in monitoring them. Our method decouples the treatment of these events from the rest of the reactions in a systematic way, thereby dramatically increasing the efficiency of the corresponding KMC algorithm. It is also making use of a very rich kinetic model which includes 5 species (H, SiH3, SiH2, SiH, and Si 2H5) that participate in 29 reactions. We have applied the new method in simulations of silicon growth under several conditions (in particular, silane fraction in the gas mixture), including those usually realized in actual PECVD technologies. This has allowed us to directly compare against available experimental data for the growth rate, the mesoscale morphology, and the chemical composition of the deposited film as a function of dilution ratio.open1

Haematological response of cyclists after competition

The aim of the study was to analyze the hematologic response of cyclists after a nationwide competition level. Participated in 20 athletes (35 ± 7,90 years old, 1,75 ± 0,06m of height, 18,71 ± 4,12% of body fat, VO2max 57,90 ± 6,80 ml/kg/min, 345 ± 50,90W, 202 ± 6,77bpm of maximum heart rate), which underwent two blood samples, monitoring of body weight and water intake. After the competition was observed decrease in body weight (78,20 ± 9,10 to 76,70 ± 9,20 kg, p = 0,0001) with an average consumption of 620 ± 532,20 mL of water, and a significant increase (p = 0,0001) in the concentration of erythrocytes (5,28 ± 0,44 6 ± 0,41 million/mm3), hemoglobin (15,80 ± 1 to 17,70 ± 0,95 g/%), the platelets (211.950 ± 42.488,2 to 285.050 ± 47.097,2 un/mm3) and hematocrit (47 ± 2,97 to 54 ± 2,79%). Strong correlation (r > 0.7) between hematocrit with erythrocytes level and hemoglobin was observed. It was concluded that there is an increase in the number of hematological components of cyclists after competition with weak correlation with the water intake, body weight and the maximum volume of oxygen levelO objetivo do estudo foi analisar a reposta hematológica de ciclistas após uma competição de nível nacional. Participaram 20 atletas (35 ± 7,90 anos, 1,75 ± 0,06m de estatura, 18,71 ± 4,12% de gordura, VO2máx de 57,90 ± 6,80 ml/kg/min, 345 ± 50,90W, 202 ± 6,77 bpm de frequência cardíaca máxima), que passaram por duas coletas de sangue, monitoramento do peso corporal e da ingesta de água. Após a competição foi verificada queda no peso corporal (78,20 ± 9,10 para 76,70 ± 9,20 kg, p = 0,0001) com consumo médio de 620 ± 532,20 ml de água, e aumento significativo (p = 0,0001) na concentração de eritrócitos (5,28 ± 0,44 para 6 ± 0,41 milhões/mm3), de hemoglobina (15,80 ± 1 para 17,70 ± 0,95 g/%), de plaquetas (211.950 ± 42.488,20 para 285.050 ± 47.097,20 un/mm3) e hematócrito (47 ± 2,97 para 54 ± 2,79%). Foi verificada forte correlação (r > 0,7) entre o hematócrito com o nível de eritrócitos e de hemoglobina. Concluiu-se que existe aumento na quantidade dos componentes hematológicos em ciclistas após competição, com fraca correlação com a ingesta voluntária de água, peso corporal e nível do volume máximo de oxigêni

The impact of language barriers on trust formation in multinational teams

This study systematically investigates how language barriers influence trust formation in multinational teams (MNTs). Based on 90 interviews with team members, team leaders, and senior managers in 15 MNTs in three German automotive corporations, we show how MNT members’ cognitive and emotional reactions to language barriers influence their perceived trustworthiness and intention to trust, which in turn affect trust formation. We contribute to diversity research by distinguishing the exclusively negative language effects from the more ambivalent effects of other diversity dimensions. Our findings also illustrate how surface-level language diversity may create perceptions of deep-level diversity. Furthermore, our study advances MNT research by revealing the specific influences of language barriers on team trust, an important mediator between team inputs and performance outcomes. It thereby encourages the examination of other team processes through a language lens. Finally, our study suggests that multilingual settings necessitate a reexamination and modification of the seminal trust theories by Mayer, Davis and Schoorman (1995) and McAllister (1995). In terms of practical implications, we outline how MNT leaders can manage their subordinates’ problematic reactions to language barriers and how MNT members can enhance their perceived trustworthiness in multilingual settings

Language in international business: a review and agenda for future research

A fast growing number of studies demonstrates that language diversity influences almost all management decisions in modern multinational corporations. Whereas no doubt remains about the practical importance of language, the empirical investigation and theoretical conceptualization of its complex and multifaceted effects still presents a substantial challenge. To summarize and evaluate the current state of the literature in a coherent picture informing future research, we systematically review 264 articles on language in international business. We scrutinize the geographic distributions of data, evaluate the field’s achievements to date in terms of theories and methodologies, and summarize core findings by individual, group, firm, and country levels of analysis. For each of these dimensions, we then put forward a future research agenda. We encourage scholars to transcend disciplinary boundaries and to draw on, integrate, and test a variety of theories from disciplines such as psychology, linguistics, and neuroscience to gain a more profound understanding of language in international business. We advocate more multi-level studies and cross-national research collaborations and suggest greater attention to potential new data sources and means of analysis

PUBLIC AND PRIVATE IMPERATIVES OF GREEK HEALTH POLICIES

Health care in Greece has historically developed into a multi-tier system, a mosaic of public and private providers of services covering the members of occupational social insurance organizations. In 1983 PASOK’s socialist government established a unified National Health System. The aim was to arrest the growth of the private sector and promote the public sector to a dominant position. The socialist legislation has recently been reviewed by a conservative government that aims at a competitive mixed market of public and private providers. The growth of private health care, however, is not solely a matter of political support but also of new opportunities for profitable investments that arise from a shrinking public sector under economic and fiscal constraints

Microscopic Dynamics and Topology of Polymer Rings Immersed in a Host Matrix of Longer Linear Polymers: Results from a Detailed Molecular Dynamics Simulation Study and Comparison with Experimental Data

We have performed molecular dynamics (MD) simulations of melt systems consisting of a small number of long ring poly(ethylene oxide) (PEO) probes immersed in a host matrix of linear PEO chains and have studied their microscopic dynamics and topology as a function of the molecular length of the host linear chains. Consistent with a recent neutron spin echo spectroscopy study (Goossen et al., Phys. Rev. Lett. 2015, 115, 148302), we have observed that the segmental dynamics of the probe ring molecules is controlled by the length of the host linear chains. In matrices of short, unentangled linear chains, the ring probes exhibit a Rouse-like dynamics, and the spectra of their dynamic structure factor resemble those in their own melt. In striking contrast, in matrices of long, entangled linear chains, their dynamics is drastically altered. The corresponding dynamic structure factor spectra exhibit a steep initial decay up to times on the order of the entanglement time τe of linear PEO at the same temperature but then they become practically time-independent approaching plateau values. The plateau values are different for different wavevectors; they also depend on the length of the host linear chains. Our results are supported by a geometric analysis of topological interactions, which reveals significant threading of all ring molecules by the linear chains. In most cases, each ring is simultaneously threaded by several linear chains. As a result, its dynamics at times longer than a few τe should be completely dictated by the release of the topological restrictions imposed by these threadings (interpenetrations). Our topological analysis did not indicate any effect of the few ring probes on the statistical properties of the network of primitive paths of the host linear chains

A new equation for the mean free path of air

A recent rigorous methodology for determining the mean free path, λ, of air at ambient conditions [Tsalikis, D. G., Mavrantzas, V. G., & Pratsinis, S. E. (2023). Physics of Fluids, 35, 097131] is extended to pressures, P, from 0.5 to 5 atm and temperatures, T, from 100 to 3000 K that are of environmental and industrial relevance, allowing to derive a new simple equation for λ as a function of T and P. This entails molecular dynamics (MD) simulations of air accounting for the actual shape and force field of nitrogen and oxygen and analysis of the computed microcanonical ensemble of free paths to derive λ at any P and T. Simulations are rigorously validated by comparing MD-predicted air densities, diffusivities and viscosities at various temperatures and pressures against experimental measurements, theoretical expressions and ab initio simulations. At all T and P, the MD-computed λ are systematically smaller (at least 40%) than those from classic kinetic theory and its variants. The new equation for λ is: λ (T, P) = 0.033916 x T¹.²³ P⁻¹ and can be also expressed in terms of the standard Jennings’ expression, λ = √(π/8) μ/u 1/√(ϱP) [Jennings, S. G. (1998). Journal of Aerosol Science, 19(2), 159–166], relating λ to air viscosity, μ, and density, ρ, using just a new value for its numerical factor u, u = 0.81475 ± 0.00288, which is 63% larger than the current u = 0.4987445.ISSN:0278-6826ISSN:1521-738