216 research outputs found

    Effects of fuel composition on charge preparation, combustion and knock tendency in a high performance GDI engine. Part I: RANS analysis

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    The paper analyses the effects of fuel composition modelling in a turbocharged GDI engine for sport car applications. Particularly, a traditional single-component gasoline-surrogate fuel is compared to a seven-component fuel model available in the open literature. The multi-component fuel is represented using the Discrete-Continuous-Multi-Component modelling approach, and it is specifically designed in order to match the volatility of an actual RON95 European gasoline. The comparison is carried out following a detailed calibration with available experimental measurements for a full load maximum power engine speed operation of the engine, and differences are analyzed and critically discussed for each of the spray evolution, mixture stratification and combustion. In the present paper (Part I), a RANS approach is used to preliminarily investigate the behaviour of the fuel model on the average engine cycle. In the subsequent Part II of the same paper, the numerical framework is evolved into a more refined LES approach, in order to take into account cycle-to-cycle variations in mixture formation and knock tendency

    Effects of fuel composition on charge preparation, combustion and knock tendency in a high performance GDI engine. Part II: Les analysis

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    As discussed in the Part I of this paper, a numerical activity is carried out in order to analyse the effects of fuel composition modelling in a turbocharged GDI engine for sport car applications. While Part I analyses the "ensemble averaged" macroscopic effects on spray evolution, mixture stratification, combustion and knock tendency, in Part II of this paper cycle-to-cycle variations are analysed and discussed using a multi-cycle LES numerical framework, again comparing results from a more traditional single-component fuel surrogate model to those of a multi-component one. A purposely developed numerical approach is applied to properly account for the effects of the Discrete-Continuous-Multi-Component fuel formulation on the charge preparation: just before the spark timing, each vaporized fuel fraction is lumped back into a single-component surrogate fuel to allow the combustion model (ECFM-3Z, in its LES formulation) to take place. At the beginning of a new injection process, the numerical framework for the injected spray is switched back to Multi-Component, thus allowing each fuel fraction to independently spread, vaporize and diffuse in the combustion chamber according to the cycle-specific characteristics. A detailed comparison between the two fuel formulations is carried out on both average and rms values of the most influencing fields just before the spark discharge

    O casamento “homoafetivo” e a política da sexualidade : implicações do afeto como justificativa das uniões de pessoas do mesmo sexo

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    No Brasil, as justificativas jurídicas para a realização de uniões entre pessoas do mesmo sexo estão assentadas no aspecto afetivo das relações com o uso do termo “homoafetividade”. O objetivo deste estudo é questionar essas justificativas, apontando para as suas repercussões políticas e subjetivas. Os argumentos foram examinados a partir de uma análise de discurso foucaultiana e confrontados com o debate sobre o direto democrático à sexualidade no contexto político e social brasileiro contemporâneo. A análise indica que o Estado está legislando modelos de afeto em vez de garantir um direito democrático da sexualidade, ou seja, usando o discurso do amor romântico e produzindo, mesmo que implicitamente, um quadro regulamentar para as subjetividades com base em demandas particulares. A conclusão apresenta a necessidade de uma justificativa sustentada nos direitos fundamentais (liberdade, igualdade, não-discriminação), os quais, uma vez garantidos, permitiriam que uma esfera pública, laica, formal, universal e abstrata, possa atender aos interesses dos indivíduos, inclusive àqueles baseados no amor romântico, sem ser reduzida a ele

    Hyperalphalipoproteinemia and Beyond: The Role of HDL in Cardiovascular Diseases

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    Hyperalphalipoproteinemia (HALP) is a lipid disorder characterized by elevated plasma high-density lipoprotein cholesterol (HDL-C) levels above the 90th percentile of the distribution of HDL-C values in the general population. Secondary non-genetic factors such as drugs, pregnancy, alcohol intake, and liver diseases might induce HDL increases. Primary forms of HALP are caused by mutations in the genes coding for cholesteryl ester transfer protein (CETP), hepatic lipase (HL), apolipoprotein C-III (apo C-III), scavenger receptor class B type I (SR-BI) and endothelial lipase (EL). However, in the last decades, genome-wide association studies (GWAS) have also suggested a polygenic inheritance of hyperalphalipoproteinemia. Epidemiological studies have suggested that HDL-C is inversely correlated with cardiovascular (CV) risk, but recent Mendelian randomization data have shown a lack of atheroprotective causal effects of HDL-C. This review will focus on primary forms of HALP, the role of polygenic inheritance on HDL-C, associated risk for cardiovascular diseases and possible treatment options

    Impact of hospital mergers. A systematic review focusing on healthcare quality measures

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    Background Despite mergers have increasingly affected hospitals in the recent decades, literature on the impact of hospitals mergers on healthcare quality measures (HQM) is still lacking. Our research aimed to systematically review evidence regarding the impact of hospital mergers on HQM focusing especially on process indicators and clinical outcomes. Methods The search was carried out until January 2020 using the Population, Intervention, Comparison and Outcome model, querying electronic databases (MEDLINE, Scopus, Web Of Science) and refining the search with hand search. Studies that assessed HQM of hospitals that have undergone a merger were included. HQMs were analyzed through a narrative synthesis and a strength of the evidence analysis based on the quality of the studies and the consistency of the findings. Results The 16 articles, included in the narrative synthesis, reported inconsistent findings and few statistically significant results. All indicators analyzed showed an insufficient strength of evidence to achieve conclusive results. However, a tendency in the decrease of the number of beds, hospital staff and inpatient admissions and an increase in both mortality and readmission rate for acute myocardial infarction and stroke emerged in our analysis. Conclusions In our study, there is no strong evidence of improvement or worsening of HQM in hospital mergers. Since a limited amount of studies currently exists, additional studies are needed. In the meanwhile, hospital managers involved in mergers should adopt a clear evaluation framework with indicators that help to periodically and systematically assess HQM ascertaining that mergers ensure and primarily do not reduce the quality of care

    Exigências Agroclimáticas das Culturas Energéticas no Brasil

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    O estudo agroclimático é uma ferramenta de grande importância para o planejamento agricola, ja que visa o conhecimento das condições das regiões em que determinadas culturas serão introduzidas para assim ter uma redução dos riscos relacionados a o clima. Conhecer os fatores que influenciam no desenvolvimento e na produtividade das culturas permite distinguir quais as áreas de melhor produtividade. Culturas com grande potencial energético estão começando a destacar-se no cenário de produção de energia nacional, assim o estudo das características climáticas da região onde esses cultivares serão introduzidos tende a diminuir o risco para os produtores

    Prevalence and Predictors of Out-of-Target LDL Cholesterol 1 to 3 Years After Myocardial Infarction. A Subanalysis From the EYESHOT Post-MI Registry

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    Background: There is an incomplete understanding of the prevalence and predictors of attainment of low-density lipoprotein cholesterol (LDL-C) goal after myocardial infarction (MI). Aim: To evaluate the prevalence of achievement of LDL-C goal of 70 mg/dL, to identify the baseline features associated with suboptimal lipid control, and to assess the use of LDL-C-lowering drug therapies (LLT) beyond the first year after MI. Methods: The EYESHOT Post-MI was a prospective, cross-sectional, Italian registry, which enrolled patients presenting to cardiologist 1 to 3 years after MI. In this retrospective post-hoc analysis, patients were categorized in 2 groups according to the achievement or not of the LDL-C goal of 70 mg/dL. Univariable and multivariable logistic regression analyses were performed to identify the baseline features associate with LDL-C >= 70 mg/dL. Results: The study population included 903 patients (mean age 65.5 +/- 11.5 years). Among them, LDL-C was >= 70 mg/dL in 474 (52.5%). Male sex (p = 0.031), hypertension (p = 0.024), prior percutaneous coronary intervention (p = 0.016) and high education level (p = 0.008) were higher in the LDL-C < 70 group. At multivariable analysis, low education level was an independent predictor of LDL-C >= 70 mg/dL (OR:1.582; 95%CI, 1.156-2.165; p = 0.004). Conversely, hypertension increased the probability to achieve the LDL-C goal (OR:0.650; 95%CI, 0.443-0.954; p = 0.028). Among off-target patients, LLT was not modified in the majority of cases (67.3%), intensified in 85 (18.6%), and actually reduced in 63 patients (13.8%). Conclusions: In patients presenting to cardiologists 1 to 3 years from the last MI event, LDL-C is not under control in a large proportion of patients, particularly in those with a low education level or without hypertension. LLT is underused in this very-high-risk setting

    Modelling Environmental Niche for the Endangered Crayfish Austropotamobius pallipesComplex in Northern and Central Italy

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    The potential distribution of endangered species is a necessary step to assess species conservation status and manage reintroduction plans. In the context of a EU project on the endangered Austropotamobius pallipescomplex, we modelled the environmental niche of the species in two large areas of Northern (Lombardy, 43 records) and Central Italy (Abruzzo, Province of Isernia, Gran Sasso e Monti della Laga National Park; 69 records). Ecological niche models (ENMs) were built by using the maximum entropy approach as implemented in the MaxEnt software, which predicts the occurrence of a species using presence-only data. The environmental niche was modelled using six variables: altitude, slope, aspect, human disturbance, mean temperature of warmest quarter and distance from stream. Each study area was modelled independently. Both ENMs obtained high performance scores as measured by the AUC index (Northern Italy: 0.854; Central Italy: 0.817). Slope in Northern Italy and the mean temperature of warmest quarter in Central Italy achieved the greatest predictive power. Our results clearly show that the endangered white-clawed crayfish has a narrow range of habitat selection in the two study areas. Our findings may help researchers to select the best sites for future reintroductions in conservation projects
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