303 research outputs found
Flowmeter and Ground Penetrating Radar: comparison between hydrogeological and geophysical methods
We discuss a comparison between saturated hydraulic conductivity calculated with Electromagnetic Borehole Flowmeter (EBF) and water content obtained by Ground Penetrating Radar (GPR) Zero Offset Profile (ZOP
Thermal and thermo-oxidative stability and kinetics of decomposition of PHBV/sisal composites
The decomposition behaviours of composites made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and sisal were assessed in terms of thermal stability and decomposition kinetics, under inert and oxidative conditions, by means of multi-rate linear non-isothermal thermogravimetric experiments. A statistical design of experiments was applied to study the influence of the addition of sisal (0-10-20-30%wt), the presence coupling agent (Yes/No) and the applied conditions of work (inert or oxidative). An improvement of the thermal and thermo-oxidative stability of PHBV with the addition of sisal was observed for all cases. An accurate methodology based on iso-conversional methods was applied to simulate the potential of thermal recovery technologies, such as pyrolysis and controlled combustion, to use these biocomposites after the end of their service life. The mathematical descriptions of both thermo-chemical reactions were helpful in the evaluation of the eventual optimal operational conditions to carry out a suitable energetic valorisation. A minimum of 240°C and 137 kJ/mol of activation energy in inert conditions and 236°C and 118 kJ/mol in oxidative conditions ensured the feasibility of the reactions regardless the composition of the PHBV/sisal biocomposites, which may ease the operability of further energy valorisation with the aim to turn biowaste into new fuels
Os sistemas agroflorestais como alternativa de sustentabilidade em ecossistemas de várzea no Amazonas.
Os sistemas agroflorestais (SAFs) representam uma alternativa agroecológica de produção, sob regime sustentável, para os agricultores familiares na várzea dos Rios Solimões/Amazonas, principalmente no que se refere ao manejo florestal, à diversidade de produtos e à geração de renda. Diante disso, o objetivo deste trabalho foi compreender as diferentes formas de apropriação e de manejo dos recursos naturais através dos SAFs, nos subsistemas roça, sítio e lagos, como componente para a sustentabilidade dos agricultores familiares da localidade Costa da Terra Nova, município do Careiro da Várzea, Amazonas. O método empregado foi o Estudo de Caso com aplicação de questionários, entrevistas e observação participante. A produção familiar na Costa da Terra Nova é representada pelos SAFs, constituído pelos os subsistemas: roça quintal e lago, que proporcionam produtos tanto para subsistência quanto para comercialização local, e estabelecendo a agricultura como fundamental atividade na localidade. O principal produto para comercialização é obtido das hortaliças cultivadas na época da vazante no subsistema roça nas comunidades São Francisco e Nossa Senhora da Conceição; e do extrativismo pesqueiro no subsistema lago, na época da cheia, principalmente na comunidade São José. A criação de animal se dá no subsistema sítio e é apenas para subsistência, sendo as aves e os suínos os principais animais domésticos criados nas três comunidades. Portanto os SAFs tradicionais, constituídos pelos subsistemas, roça, sitio e lago, são responsáveis pela sustentabilidade socioeconômica da localidade pesquisada, servindo, como alternativa agrícola melhor adaptada às condições locais das áreas de várzea na Amazônia
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The 1930s as black mirror: Visions of historical repetition in the global financial press, 2007-2009
Media coverage of the recent financial crisis has referred extensively to various past crises, and in particular to the events of the 1930s. This article suggests that the idea of the Great Depression has effectively come to function as a kind of historical ‘black mirror’ – a quasi-object within which conjuncture and historical representation interact to produce an image of capitalist history itself. Focusing on the journalistic output of four key financial publications, I trace how portrayals of the 1930s have evolved over the course of the crisis. I find that while the 1930s are frequently and consistently invoked in ways that purport to reveal the historicity of the crisis, these representations produce an oscillation between different visions of historical repetition, which in turn underpin competing interpretations of the crisis as it unfolds. In so doing, I argue, appeals to the 1930s have simultaneously served to conceal and disclose the constitutive relation of historical imagination to historical process – a double move that has had the paradoxical effect of both securing and undermining the reproduction of finance capitalism as we have come to know it
The dynamics of experiencing Gestalt and Aha in cubist art: pupil responses and art evaluations show a complex interplay of task, stimuli content, and time course
IntroductionGestalt perception refers to the cognitive ability to perceive various elements as a unified whole. In our study, we delve deeper into the phenomenon of Gestalt recognition in visual cubist art, a transformative process culminating in what is often described as an Aha moment. This Aha moment signifies a sudden understanding of what is seen, merging seemingly disparate elements into a coherent meaningful picture. The onset of this Aha moment can vary, either appearing almost instantaneously, which is in line with theories of hedonic fluency, or manifesting after a period of time, supporting the concept of delayed but more in-depth meaningful insight.MethodsWe employed pupillometry to measure cognitive and affective shifts during art interaction, analyzing both maximum pupil dilation and average dilation across the trial. The study consisted of two parts: in the first, 84 participants identified faces in cubist paintings under various conditions, with Aha moments and pupil dilation measured. In part 2, the same 84 participants assessed the artworks through ratings in a no-task free-viewing condition.ResultsResults of part 1 indicate a distinctive pattern of pupil dilation, with maximum dilation occurring at both trial onset and end. Longer response times were observed for high-fluent, face-present stimuli, aligning with a delayed but accurate Aha-moment through recognition. Additionally, the time of maximum pupil dilation, rather than average dilation, exhibited significant associations, being later for high-fluent, face-present stimuli and correct detections. In part 2, average, not the time of maximum pupil dilation emerged as the significant factor. Face-stimuli and highly accessible art evoked stronger dilations, also reflecting high clearness and negative valence ratings.DiscussionThe study underscores a complex relationship between the timing of recognition and the Aha moment, suggesting nuanced differences in emotional and cognitive responses during art viewing. Pupil dilation measures offer insight into these processes especially for moments of recognition, though their application in evaluating emotional responses through artwork ratings warrants further exploration
1989 as a mimetic revolution: Russia and the challenge of post-communism
Various terms have been used to describe the momentous events of 1989, including Jürgen Habermas’s ‘rectifying revolution,’ and my own notion of 1989 as a type of ‘anti-revolution’: repudiating not only what had come before, but also denying the political logic of communist power, as well as the emancipatory potential of revolutionary socialism in its entirety. In the event, while the negative agenda of 1989 has been fulfilled, it failed in the end to transcend the political logic of the systems that collapsed at that time. This paper explores the unfulfilled potential of 1989. Finally, 1989 became more of a counter- rather than an anti-revolution, replicating in an inverted form the practices of the mature state socialist regimes. The paucity of institutional and intellectual innovation arising from 1989 is striking. The dominant motif was ‘returnism,’ the attempt to join an established enterprise rather than transforming it. Thus, 1989 can be seen as mimetic revolution, in the sense that it emulated systems that were not organically developed in the societies in which they were implanted. For Eastern Europe ‘returning’ to Europe appeared natural, but for Russia the civilizational challenge of post-communism was of an entirely different order. There could be no return, and instead of a linear transition outlined by the classic transitological literature, Russia’s post-communism demonstrated that the history of others could not be mechanically transplanted from one society to another
Sertoli Cells as potential Pharmaceutical Carriers: uptake and stability
Sertoli cells (SC) have been used for their immunomodulatory properties in cell transplants (Emerich et al., 2003). Moreover, SC themselves may prevent immune rejection (Sipone et al., 2006) and possess a natural phagocytic activity: the latter may make them suitable as biocompatible drug delivery carriers. Porcine SC were loaded with PLA microspheres containing pharmaceutical agents (SC-MS). Phagocytosis was monitored over 24 hours; the uptake was measured by HPLC at fixed time points and followed up through 6 days. SC viability and morphology were monitored together with reactive oxygen species (ROS), DNA damage and parameters of SC functionality and immunomodulatory properties over time. A preliminary antibacterial activity was assessed in vitro. SC-MS were cryopreserved in liquid nitrogen and after plating underwent the same characterization. SC internalized drug loaded MS with an uptake rate of about 20% at 5 hours, that increased by 30% until day two. The uptake was stable up to 6 days with no differences in ROS, DNA damage, functional and immunomodulatory properties observed between control and loaded SC, even after cryopreservation/thawing. A spontaneous in vitro activity against pseudomonas strain, presented with SC alone, increased in presence of MS, and was maintained after cryoperservation. These results encourage further studies to understand the real potential of SC as drug delivery vehicles in trials in “in vivo” animal models
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