1,492 research outputs found

    Production Leveling (Heijunka) Implementation in a Batch Production System: a Case Study

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    Abstract: This paper presents a case study of an implementation of a new method for Production Leveling designed for batch production. It includes prioritizing criteria of products and level production plan. Moreover, it was applied on a subsidiary of a multinational enterprise located on Brazil, which manufacturing processes comprise batch production in a make-to-stock policy. Regarding a qualitative assessment, evidences show that the company had deficient practices related to Operations Planning. Thus, based on a case study approach, proposed method was applied as well empirical data were analyzed. Results were measured before and after this implementation by performance indicators of Costs (inventory), Speed (lead time), Mix flexibility (monthly set up operations) and Reliability (service level). Evidences confirm improvements in operational efficiency as expected. Researchers and practitioners can evaluate general applicability of this method by applying it in different companies that share similarities related to batch processing operations

    The modulation of the symbiont/host interaction between wolbachia pipientis and aedes fluviatilis embryos by glycogen metabolism

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    Wolbachia pipientis, a maternally transmitted bacterium that colonizes arthropods, may affect the general aspects of insect physiology, particularly reproduction. Wolbachia is a natural endosymbiont of Aedes fluviatilis, whose effects in embryogenesis and reproduction have not been addressed so far. In this context, we investigated the correlation between glucose metabolism and morphological alterations during A. fluviatilis embryo development in Wolbachia-positive (W+) and Wolbachia-negative (W2) mosquito strains. While both strains do not display significant morphological and larval hatching differences, larger differences were observed in hexokinase activity and glycogen contents during early and mid-stages of embryogenesis, respectively. To investigate if glycogen would be required for parasite-host interaction, we reduced Glycogen Synthase Kinase-3 (GSK-3) levels in adult females and their eggs by RNAi. GSK-3 knock-down leads to embryonic lethality, lower levels of glycogen and total protein and Wolbachia reduction. Therefore, our results suggest that the relationship between A. fluviatilis and Wolbachia may be modulated by glycogen metabolism

    Is chemical exposure present in informal work associated with Sars-CoV-2 infection?

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    OBJECTIVE: To compare the incidence of Covid-19 symptoms between informal home-based workers and a control group and to assess the association of these cases with blood elements concentrations and other relevant risk factors for Sars-Cov-2 infection. METHODS: Welders chemically exposed to potentially toxic elements (PTEs) (n = 26) and control participants (n = 25) answered questionnaires on adherence to social distancing and signs and symptoms of the disease for five months during the Covid-19 pandemic. After follow-up, Covid-19 serology tests were performed on a subsample of 12 chemically exposed workers and 20 control participants. Before the pandemic, PTE concentrations in blood (As, Mn, Ni, Cd, Hg, Sb, Sn, Cu, Zn, and Pb) were measured by ICP-MS. RESULTS: The chemically exposed group had higher lead and cadmium levels in blood (p < 0.01). The control group presented lower adherence to social distancing (p = 0.016). Although not significant, welders had a 74% greater chance of having at least one Covid-19 symptom compared with control participants, but their adherence to social distancing decreased this chance by 20%. The use of taxis for transportation was a risk factor significantly associated with Covid-19 symptoms. CONCLUSION: The lower adherence to social distancing among the control group greatly influences the development of Covid-19. The literature lacks data linking exposure to PTEs and Sars-Cov-2 infection and/or severity. In this study, despite chemical exposure, working from home may have protected welders against Covid-19, considering that they maintained greater social distancing than control participants

    “Quem ensina tambĂ©m aprende” : a formação pela prĂĄtica de professores primĂĄrios na provĂ­ncia do ParanĂĄ

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    Resumo Segundo a historiografia da educação brasileira, muitas foram as açÔes relacionadas aos modos de formar professores primĂĄrios durante o perĂ­odo imperial. Desses estudos, a maioria se centra na formação de professores atrelada Ă  instituição das escolas normais, entretanto, hĂĄ uma parcela menor de trabalhos que se propĂ”em a discutir outro aspecto da formação de professores ao longo do sĂ©culo XIX, mais especificamente, a forma como sujeitos que nĂŁo frequentaram esse espaço institucional (a escola normal), constituĂ­ram-se docentes primĂĄrios. O artigo que aqui se apresenta partilha dessa perspectiva, e volta o olhar para os modos de formação pela prĂĄtica de professores primĂĄrios no ParanĂĄ na segunda metade do sĂ©culo XIX, por compreender que esse tipo de formação marcou um perĂ­odo em que a instrução pĂșblica estava se consolidando em meio a açÔes, deliberaçÔes, dificuldades e tensĂ”es, na tentativa de melhorias de sua condição. A pesquisa valeu-se da consulta da legislação educacional do perĂ­odo e de documentos advindos dos sujeitos envolvidos com a instrução pĂșblica, naquele momento, disponĂ­veis no acervo do Arquivo PĂșblico do ParanĂĄ. No cotejamento e anĂĄlise das fontes, Ă© possĂ­vel afirmar, que a formação pela prĂĄtica dos professores primĂĄrios na provĂ­ncia do ParanĂĄ se deu no decorrer do desenvolvimento do processo de constituição do magistĂ©rio primĂĄrio

    O urbanismo conveniente luso-brasileiro na formação de povoaçÔes em Minas Gerais no século XVIII

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    The settlement of villages in the old colonial province of Minas Gerais obeyed certain principles of what was considered decent, convenient and adequate. Such principles were based on rules, doctrines and habits inherent to the Luso-Brazilian architecture of that time. The historical analysis of these aspects leads to a critical review of some consolidated assumptions in historiography, such as the one for which the settlements aforementioned would have appeared in a spontaneous, irregular and disordered fashion. Because they are evident in the remaining settlements and period art treatises and documents, these aspects lead to the consideration of a true art of populating, based on certain values and habits, which we call convenient Luso-Brazilian urbanism.A formação de povoaçÔes na capitania de Minas Gerais no sĂ©culo XVIII estava condicionada a preceitos de decoro, conveniĂȘncia e adequação. Esses preceitos constituĂ­am regras, doutrinas e costumes muito relevantes Ă  arte luso-brasileira de edificar arquiteturas e cidades naquele tempo. A consideração histĂłrica desses aspectos nos conduz Ă  revisĂŁo crĂ­tica de uma sĂ©rie de compreensĂ”es consolidadas na historiografia, como, por exemplo, a de que essas povoaçÔes seriam espontĂąneas, irregulares e desordenadas. Pela importĂąncia com que se evidenciam nas povoaçÔes remanescentes, nos tratados artĂ­sticos e nos documentos coevos, tais aspectos nos levam a cogitar em uma verdadeira arte de povoar fundamentada nesses valores e costumes, arte a que denominamos urbanismo conveniente luso-brasileiro

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

    Pervasive gaps in Amazonian ecological research

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    An embedding technique to determine ττ backgrounds in proton-proton collision data

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    An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

    Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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