6,925 research outputs found

    Variable sediment oxygen uptake in response to dynamic forcing

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    Seiche-induced turbulence and the vertical distribution of dissolved oxygen above and within the sediment were analyzed to evaluate the sediment oxygen uptake rate (JO2), diffusive boundary layer thickness (δDBL), and sediment oxic zone depth (zmax) in situ. High temporal-resolution microprofiles across the sediment-water interface and current velocity data within the bottom boundary layer in a medium-sized mesotrophic lake were obtained during a 12-h field study. We resolved the dynamic forcing of a full 8-h seiche cycle and evaluated JO2 from both sides of the sediment-water interface. Turbulence (characterized by the energy dissipation rate, ε), the vertical distribution of dissolved oxygen across the sediment-water interface (characterized by δDBL and zmax), JO2, and the sediment oxygen consumption rate (RO2) are all strongly correlated in our freshwater system. Seiche-induced turbulence shifted from relatively active (ε = 1.2 × 10-8 W kg-1) to inactive (ε = 7.8 × 10-12 W kg-1). In response to this dynamic forcing, δDBL increased from 1.0 mm to the point of becoming undefined, zmax decreased from 2.2 to 0.3 mm as oxygen was depleted from the sediment, and JO2 decreased from 7.0 to 1.1 mmol m-2 d-1 over a time span of hours. JO2 and oxygen consumption were found to be almost equivalent (within ~ 5% and thus close to steady state), with RO2 adjusting rapidly to changes in JO2. Our results reveal the transient nature of sediment oxygen uptake and the importance of accurately characterizing turbulence when estimating JO2

    Time, DNA and documents in family reckonings

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    In this paper, drawing on literature from both STS and the anthropology of kinship, we describe a political movement aimed at legal reparation for human rights violations perpetrated by the Brazilian government against children of the compulsorily institutionalized patients of Hansen’s disease. We conduct our investigation by exploring the action of intertwining technologies – narrated recollections, written documents, and the DNA test – employed by major actors to “reckon” the family connections at the core of this drama. The notion of technologies helps underline not only the materiality of certain processes, but also the complex temporalities at play. Responding to a challenge proposed by Janet Carsten, our ultimate aim is to show how political events as well as collective institutionalized structures – operating through the mediation of these diverse technologies – produce a particular kind of sociality, interwoven with perceptions of family and community.Neste artigo, com inspiração tanto nos estudos da ciência quanto na antropologia do parentesco, descrevemos um movimento político que exige do governo brasileiro reparação legal pela violação dos direitos humanos dos filhos de pessoas compulsoriamente internadas por causa da Hanseníase. Realizamos essa investigação através do exame de três tecnologias interconectadas – narrativas orais, documentos escritos e o teste de DNA – usadas pelos atores principais para “calcular” as conexões familiares no cerne desse drama. A noção de tecnologias permite destacar não só a materialidade de certos processos, mas também as temporalidades complexas em jogo. Ao responder a um desafio lançado por Janet Carsten, nosso objetivo último é demostrar como eventos políticos assim como estruturas institucionalizadas coletivas – mediadas por essas diversas tecnologias – produzem um tipo particular de socialidade, enredada em percepções novas de família e comunidade

    Extra nuclear localization of steroid receptors and non genomic activation mechanisms

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    Los receptores de hormonas esteroides han sido considerados históricamente como factores de transcripción nucleares. Sin embargo, en los últimos años surgieron evidencias que indican que su activación desencadena eventos rápidos, independientes de la transcripción y que involucran a diferentes segundos mensajeros; muchos de estos receptores han sido localizados en la membrana celular. Por otra parte, se han caracterizado varios receptores de hormonas esteroides noveles, de estructura molecular diferente al receptor clásico, localizados principalmente en la membrana celular. Esta revisión enfoca los diferentes efectos iniciados por los glucocorticoides, mineralocorticoides, andrógenos, estrógenos y progesterona, y los posibles receptores involucrados en los mismos.Steroid hormone receptors have been historically considered as nuclear transcription factors. Nevertheless, in the last years, many of them have been detected in the cellular membrane. It has been postulated that their activation can induce transcription independent rapid events involving different second messengers. In addition, several novel steroid hormone receptors, showing a different molecular structure than the classical ones, have also been characterized and most of them are also located in the plasmatic membrane. This review focuses on the variety of effects initiated by glucocorticoids, mineralocorticoids, androgens, estrogens and progesterone, and the possible receptors involved mediating these effects.Fil: Bottino, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Lanari, Claudia Lee Malvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentin

    Text Processing Like Humans Do: Visually Attacking and Shielding NLP Systems

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    Visual modifications to text are often used to obfuscate offensive comments in social media (e.g., "!d10t") or as a writing style ("1337" in "leet speak"), among other scenarios. We consider this as a new type of adversarial attack in NLP, a setting to which humans are very robust, as our experiments with both simple and more difficult visual input perturbations demonstrate. We then investigate the impact of visual adversarial attacks on current NLP systems on character-, word-, and sentence-level tasks, showing that both neural and non-neural models are, in contrast to humans, extremely sensitive to such attacks, suffering performance decreases of up to 82\%. We then explore three shielding methods---visual character embeddings, adversarial training, and rule-based recovery---which substantially improve the robustness of the models. However, the shielding methods still fall behind performances achieved in non-attack scenarios, which demonstrates the difficulty of dealing with visual attacks.Comment: Accepted as long paper at NAACL-2019; fixed one ungrammatical sentenc

    AKT1 and AKT2 isoforms play distinct roles during breast cancer progression through the regulation of specific downstream proteins

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    The purpose of this study was to elucidate the mechanisms associated with the specific effects of AKT1 and AKT2 isoforms in breast cancer progression. We modulated the abundance of specific AKT isoforms in IBH-6 and T47D human breast cancer cell lines and showed that AKT1 promoted cell proliferation, through S6 and cyclin D1 upregulation, but it inhibited cell migration and invasion through β1-integrin and focal adhesion kinase (FAK) downregulation. In contrast, AKT2 promoted cell migration and invasion through F-actin and vimentin induction. Thus, while overexpression of AKT1 promoted local tumor growth, downregulation of AKT1 or overexpression of AKT2 promoted peritumoral invasion and lung metastasis. Furthermore, we evaluated The Cancer Genome Atlas (TCGA) dataset for invasive breast carcinomas and found that increased AKT2 but not AKT1 mRNA levels correlated with a worse clinical outcome. We conclude that AKT isoforms play specific roles in different steps of breast cancer progression, with AKT1 involved in the local tumor growth and AKT2 involved in the distant tumor dissemination, having AKT2 a poorer prognostic value and consequently being a worthwhile target for therapy.Fil: Riggio, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Perrone, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Polo, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Rodriguez, Maria Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: May, Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Abba, Martín Carlos. Universidad Nacional de La Plata; ArgentinaFil: Lanari, Claudia Lee Malvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Novaro, Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

    CULTURAL IDENTITY OF THE FIRST GENERATION AMERICANS: A QUALITATIVE STUDY

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    This research explores how meanings drawn from advertising and the mass media may contribute to the cultural identity of young adults who are first generation Americans and children of immigrants. We examine the meanings informants derive about U.S. culture and people, how they interpret the media portrayals of people of different national ancestries, and how such meaning-making affects their daily lives and cultural identity. A key finding is that informants experience a number of conflicts that stem from negotiating multiple and sometimes contradictory cultural messages received from the media, society, family, and friends. We explore the nature of these tensions and the role of the mass media in contributing to them. Moreover, we examine a variety of cultural identity management strategies employed by informants in dealing with these diverse influences. We close by discussing implications for advertising and media managers and avenues for future research
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