Nonlinear vibration absorber optimal design via asymptotic approach

This paper tackles the classical problem of Vibration Absorbers (VAs) operating in the nonlinear dynamic regime. Since traditional linear VAs suffer from the drawback of a narrow bandwith and numerous structures exhibit nonlinear behavior, nonlinear absorbers are of practical interest. The resonant dynamic behavior of a nonlinear hysteretic VA attached to a damped nonlinear structure is investigated analytically via asymptotics and numerically via path following. The response of the reduced-order model, obtained by projecting the dynamics of the primary structure onto the mode to control, is evaluated using the method of multiple scales up to the first nonlinear order beyond the resonance. Here, the asymptotic response of the two-degree-of-freedom system with a 1:1 internal resonance is shown to be in very close agreement with the results of path following analyses. The asymptotic solution lends itself to a versatile optimization based on differential evolutionary

Ethanol-induced changes in G-proteins gene expression

The cellular and molecular mechanism underlying addictive behaviours in humans is still not fully understood. Several studies have indicated that the expression of certain genes in the reward pathways of the central nervous system are altered following repeated exposure to addictive drugs. Our studies are focussed on ethanol and on its effect on the expression of G proteins, which are associated with several different neurotransmitter receptors. In our study we use the fruit fly Drosophila Melanogaster as a model organism. This insect displays classical tolerance behaviour when exposed to ethanol and contains the same receptors systems found in mammalian reward pathways. Our findings indicate that the expression of some of the G protein subtypes is altered following acute and chronic ethanol exposure. We have also observed that there is considerable variation among the wild type population in the response to alcohol and we are carrying out parallel studies to isolate strains of flies with different response behaviour. The work is aimed at better understanding the role of G proteins in the signalling response to ethanol in the fly. The information obtained should also further elucidate addiction mechanism in mammalian systems. This work is part of the internal collaboration of UEL’s Substance Use and Misuse (SUM) network

Amphetamine and pseudoephedrine cross-tolerance measured by c-Fos protein expression in brains of chronically treated rats

Background Pseudoephedrine is a drug commonly prescribed as a nasal decongestant and bronchodilator and is also freely available in cold remedies and medications. The structural and pharmacological similarity of pseudoephedrine to amphetamine has led to evaluation of its psychomotor stimulant properties within the central nervous system. Previous investigations have shown that the acute responses to pseudoephedrine were similar to those of amphetamine and other psychostimulants. Results This study examined the effect of chronic administration of pseudoephedrine in rat nucleus accumbens and striatum and identified three further similarities to amphetamine. (i) Chronic exposure to pseudoephedrine reduced the c-Fos response to acute pseudoephedrine treatment suggesting that pseudoephedrine induced tolerance in the animals. (ii) In animals chronically treated with amphetamine or pseudoephedrine the acute c-Fos response to pseudoephedrine and amphetamine was reduced respectively as compared to naïve animals indicating cross-tolerance for the two drugs. (iii)The known involvement of the dopamine system in the response to amphetamine and pseudoephedrine was further confirmed in this study by demonstrating that pseudoephedrine similarly to amphetamine, but with lower potency, inhibited [3H]dopamine uptake in synaptosomal preparations. Conclusion This work has demonstrated further similarities of the effect of pseudoephedrine to those of amphetamine in brain areas known to be associated with drug addiction. The most significant result presented here is the cross tolerance effect of amphetamine and psudoephedrine. This suggests that both drugs induce similar mechanisms of action in the brain. Further studies are required to establish whether despite its considerable lower potency, pseudoephedrine could pose health and addiction risks in humans similar to that of known psychostimulants

Opioid modulation of GABA release in the rat inferior colliculus

Background: The inferior colliculus, which receives almost all ascending and descending auditory signals, plays a crucial role in the processing of auditory information. While the majority of the recorded activities in the inferior colliculus are attributed to GABAergic and glutamatergic signalling, other neurotransmitter systems are expressed in this brain area including opiate peptides and their receptors which may play a modulatory role in neuronal communication.Results: Using a perfusion protocol we demonstrate that morphine can inhibit KCl-induced release of [H-3] GABA from rat inferior colliculus slices. DAMGO ([D-Ala(2), N-Me-Phe(4), Gly(5)ol]-enkephalin) but not DADLE ([D-Ala2, D-Leu5]-enkephalin or U69593 has the same effect as morphine indicating that mu rather than delta or kappa opioid receptors mediate this action. [H-3]GABA release was diminished by 16%, and this was not altered by the protein kinase C inhibitor bisindolylmaleimide I. Immunostaining of inferior colliculus cryosections shows extensive staining for glutamic acid decarboxylase, more limited staining for mu opiate receptors and relatively few neurons co-stained for both proteins.Conclusion: The results suggest that mu-opioid receptor ligands can modify neurotransmitter release in a sub population of GABAergic neurons of the inferior colliculus. This could have important physiological implications in the processing of hearing information and/or other functions attributed to the inferior colliculus such as audiogenic seizures and aversive behaviour

Payload oscillations control in harbor cranes via semi-active vibration absorbers: modeling, simulations and experimental results

Abstract Semi-active vibration absorbers (SAVAs) are proposed to suppress large amplitude oscillations in container cranes during maneu-vers and wind forcing. The SAVA design and optimization are achieved via suitable nonlinear models, numerical simulations, and laboratory as well as full-scale tests. A comprehensive nonlinear modelling, featuring a full three-dimensional crane model and the adaptive vibration control architecture, is devised. The container is modeled as a rigid body elastically suspended from the trolley traveling along the crane boom. Two identical SAVAs are studied coupling their equations of motion - which include the impact against rubberized end stops - with the container crane dynamics. Suitable parametric analyses are carried out to investigate and optimize the control devices. Full-scale experiments are performed to validate the semi-active control architecture which proves to be a feasible approach

Sobre a sociologia do trabalho e (alguns dos) seus informantes: breves anotações teórico-metodológicas

Atualmente, quando falamos em fazer uma pesquisa sociológica que tenha como recorte o tema da direção das empresas, muitos classificam esse tipo de produção como sociologia empresarial, sociologia das organizações, sociologia da gestão, ou ainda sociologia dos recursos humanos. A classificação em compartimentos temáticos é algo que faz parte de uma dinâmica própria da ciência. E isso pode acontecer tanto por razões metodológicas quanto por razões de natureza política. Longe de questionar essas razões, esse artigo pretende argumentar que algumas reflexões que, em princípio, estariam legadas a essas subdivisões, estão também umbilicalmente ligadas às discussões que permeiam a sociologia do trabalho em sua forma original. A sociologia do trabalho não é, pois, proveniente somente das narrativas e das experiências vivenciadas diretamente pelos trabalhadores. Ela deve abarcar também discussões mais amplas sobre as questões éticas, morais e ideológicas que permeiam o sistema produtivo e que, mais tarde, irão se traduzir em disciplinamento da força de trabalho e relações de poder e dominação no mundo corporativo. Para expor essas questões, tomaremos emprestada a noção foucaultiana de “sistema de pensamento” para expor possíveis correlações entre discurso e ação no que concerne aos processos de trabalho. Afinal, esse “sistema de pensamento” tem também correlação com os processos de subjetivação que se manifestam em todos os atores do mundo do trabalho – dirigentes ou dirigidos

Notas sobre una obra de Blumenbach

Resenha de: Blumenbach, J. F. Sobre o impulso de formação e a geração. Tradução, introdução e notas de Isabel Coelho Fragelli. Revisão técnica de Luciana Valéria Nogueira. Santo André: Editora UFABC, 2019Review of: Blumenbach, J. F. Sobre o impulso de formação e a geração. Tradução, introdução e notas de Isabel Coelho Fragelli. Revisão técnica de Luciana Valéria Nogueira. Santo André: Editora UFABC, 201

Mulheres e negros na produção brasileira de audiovisual: anotações empíricas pela abordagem da sociologia do trabalho

O presente texto vista realizar uma breve análise de pesquisas e dados referentes à distribuição de pessoas identificadas como mulheres e negros no âmbito da produção de cinema e televisão no Brasil. Igualmente, realizamos uma revisão bibliográfica sobre as políticas culturais voltadas ao audiovisual, tendo como recorte mecanismos de fomento associados à implementação de ações afirmativas no setor. Ao final do texto, analisamos de maneira crítica e detalhada os dados expostos e a bibliografia revisada, apontando lacunas investigativas e possibilidades de aprofundamento no campo empírico. A partir de uma abordagem sociológica, indicamos aspectos sociais e estruturais que acreditamos ser importantes para um aprofundamento empírico no recorte de pesquisa proposto.Palavras-Chave: profissionais do audiovisual; desigualdades; raça; gênero; sociologia do trabalho

MOVIMENTOS AFILIATIVOS EM INTERAÇÕES DIGITAIS: EXPLORAÇÕES EM POSTAGENS MULTIMODAIS

Drawing on insights from Systemic-Functional Linguistics and the Grammar of Visual Design, this paper explores different possibilities for individuation in verbo-pictorial Facebook posts, investigating how their different semiotic regions (their "canvases") strategically engage with potentially affiliative couplings. After locating the study along the dimensions of stratification and instantiation, we present the individuation scale as a sociosemiotic dimension and outline the main systems of the Grammar of Visual Design; then, we make explicit the model of semiotic decomposition employed in the analytical procedure; finally, we present the analyses, whose results are systematized in the concluding remarks.Tendo como base a Linguística Sistêmico-Funcional e a Gramática do Design Visual, este artigo explora diferentes possibilidades de individuação em postagens verbo-pictóricas instanciadas em um grupo de Facebook, investigando o modo como as diferentes regiões semióticas de uma postagem (suas “telas”) operam estrategicamente com acoplamentos potencialmente afiliativos. Após localizar o estudo em termos de estratificação e instanciação, apresenta-se a escala de individuação como dimensão sociossemiótica e delineiam-se os principais sistemas da Gramática do Design Visual; depois, explicita-se o modelo de decomposição semiótica empregado no procedimento analítico; enfim, apresentam-se as análises, cujos resultados são explicitados e sistematizados nas considerações finais

MÉTODO, EXPOSIÇÃO E DEFINIÇÃO NA CRÍTICA DA RAZÃO PURA DE KANT

The aim of this article consists in presenting an interpretation of the Critique of Pure Reason that begins with the notion of method in philosophy and it is way of exposition. This interpretation obeys the imperative of comprehending Kant’s philosophy as a whole and intends, doing do, point out the importance of the method in the study of kantian philosophy. After getting into the preliminary discussion about the possible interpretation of Kant’s method of philosophy and its importance, we present the method, distinguishing it from the way of exposition. After that, we present the difference between the hole of definition in mathematics and philosophy.O objetivo deste artigo consiste em apresentar uma interpretação da Crítica da razão pura que parte da noção de método da filosofia e seu modo de exposição. Essa interpretação obedece ao imperativo de compreender a filosofia de Kant como um todo, o que exige, assim, indicar certa importância da noção de método no estudo da filosofia kantiana. Após adentrar as discussões preliminares com relação às interpretações do método da filosofia de Kant e o estabelecimento da importância dele, buscamos apresentar este método, distinguindo-o do que seria modo de exposição e passando a trabalhar seguindo principalmente o papel da definição no método filosófico, que se diferencia do apresentado no método matemático