Active Brownian Particles. From Individual to Collective Stochastic Dynamics

We review theoretical models of individual motility as well as collective dynamics and pattern formation of active particles. We focus on simple models of active dynamics with a particular emphasis on nonlinear and stochastic dynamics of such self-propelled entities in the framework of statistical mechanics. Examples of such active units in complex physico-chemical and biological systems are chemically powered nano-rods, localized patterns in reaction-diffusion system, motile cells or macroscopic animals. Based on the description of individual motion of point-like active particles by stochastic differential equations, we discuss different velocity-dependent friction functions, the impact of various types of fluctuations and calculate characteristic observables such as stationary velocity distributions or diffusion coefficients. Finally, we consider not only the free and confined individual active dynamics but also different types of interaction between active particles. The resulting collective dynamical behavior of large assemblies and aggregates of active units is discussed and an overview over some recent results on spatiotemporal pattern formation in such systems is given.Comment: 161 pages, Review, Eur Phys J Special-Topics, accepte

Large-scale phenotyping of patients with long COVID post-hospitalization reveals mechanistic subtypes of disease

One in ten severe acute respiratory syndrome coronavirus 2 infections result in prolonged symptoms termed long coronavirus disease (COVID), yet disease phenotypes and mechanisms are poorly understood1. Here we profiled 368 plasma proteins in 657 participants ≥3 months following hospitalization. Of these, 426 had at least one long COVID symptom and 233 had fully recovered. Elevated markers of myeloid inflammation and complement activation were associated with long COVID. IL-1R2, MATN2 and COLEC12 were associated with cardiorespiratory symptoms, fatigue and anxiety/depression; MATN2, CSF3 and C1QA were elevated in gastrointestinal symptoms and C1QA was elevated in cognitive impairment. Additional markers of alterations in nerve tissue repair (SPON-1 and NFASC) were elevated in those with cognitive impairment and SCG3, suggestive of brain–gut axis disturbance, was elevated in gastrointestinal symptoms. Severe acute respiratory syndrome coronavirus 2-specific immunoglobulin G (IgG) was persistently elevated in some individuals with long COVID, but virus was not detected in sputum. Analysis of inflammatory markers in nasal fluids showed no association with symptoms. Our study aimed to understand inflammatory processes that underlie long COVID and was not designed for biomarker discovery. Our findings suggest that specific inflammatory pathways related to tissue damage are implicated in subtypes of long COVID, which might be targeted in future therapeutic trials

Estratégias, organização e gestão de empresas em mercados globalizados: a experiência recente do Brasil Strategies, organization and management of industrial companies in globalized markets: the recent experience of Brazil

No novo contexto de economia globalizada, as perspectivas de cada país são função das competências adquiridas por seus elementos constitutivos: pessoas, empresas, instituições. Este estudo analisa as mudanças em curso na indústria brasileira, recentemente envolvida na globalização produtiva, e suas conseqüências em termos de formação de competências. Destaca as profundas mudanças em termos de estratégias, arquiteturas organizacionais e sistemas de gestão que estão ocorrendo, tanto nas empresas estrangeiras quanto nas brasileiras. Mesmo que no curto prazo essas mudanças possam ser consideradas positivas, no longo prazos os seus efeitos serão prejudiciais para o desenvolvimento de competências locais, o que afetará o desempenho competitivo da indústria brasileira.<br>This study analyses the changes that are taking place in the Brazilian industry, recently involved in the process of productive globalization. It shows that drastic changes in terms of strategies, organization and management are in course, both in terms of transnational and Brazilian enterprises. The main conclusion is that knowledge intensive functions such as R&D, Strategic Management and Management Systems are being transferred abroad by the TNCs and the Logistics function is becoming the most "strategic" function in the operation of their subsidiaries. The Brazilian enterprises which succeed in operating in globalized productive chains are adopting similar structures. In the long run, those changes will be detrimental for the formation of local capabilities and consequently, for the maintenance of the competitive position of Brazilian industry