1,422 research outputs found

    A water level relationship between consecutive gauge stations along Solim\~oes/Amazonas main channel: a wavelet approach

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    Gauge stations are distributed along the Solim\~oes/Amazonas main channel to monitor water level changes over time. Those measurements help quantify both the water movement and its variability from one gauge station to the next downstream. The objective of this study is to detect changes in the water level relationship between consecutive gauge stations along the Solim\~oes/Amazonas main channel, since 1980. To carry out the analyses, data spanning from 1980 to 2010 from three consecutive gauges (Tefe, Manaus and Obidos) were used to compute standardized daily anomalies. In particular for infra-annual periods it was possible to detect changes for the water level variability along the Solim\~oes/Amazonas main channel, by applying the Morlet Wavelet Transformation (WT) and Wavelet Cross Coherence (WCC) methods. It was possible to quantify the waves amplitude for the WT infra-annual scaled-period and were quite similar to the three gauge stations denoting that the water level variability are related to the same hydrological forcing functions. Changes in the WCC was detected for the Manaus-Obidos river stretch and this characteristic might be associated with land cover changes in the floodplains. The next steps of this research, will be to test this hypotheses by integrating land cover changes into the floodplain with hydrological modelling simulations throughout the time-series

    Usefulness of regional right ventricular and right atrial strain for prediction of early and late right ventricular failure following a left ventricular assist device implant: A machine learning approach

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    Background: Identifying candidates for left ventricular assist device surgery at risk of right ventricular failure remains difficult. The aim was to identify the most accurate predictors of right ventricular failure among clinical, biological, and imaging markers, assessed by agreement of different supervised machine learning algorithms. Methods: Seventy-four patients, referred to HeartWare left ventricular assist device since 2010 in two Italian centers, were recruited. Biomarkers, right ventricular standard, and strain echocardiography, as well as cath-lab measures, were compared among patients who did not develop right ventricular failure (N = 56), those with acute–right ventricular failure (N = 8, 11%) or chronic–right ventricular failure (N = 10, 14%). Logistic regression, penalized logistic regression, linear support vector machines, and naïve Bayes algorithms with leave-one-out validation were used to evaluate the efficiency of any combination of three collected variables in an “all-subsets” approach. Results: Michigan risk score combined with central venous pressure assessed invasively and apical longitudinal systolic strain of the right ventricular–free wall were the most significant predictors of acute–right ventricular failure (maximum receiver operating characteristic–area under the curve = 0.95, 95% confidence interval = 0.91–1.00, by the naïve Bayes), while the right ventricular–free wall systolic strain of the middle segment, right atrial strain (QRS-synced), and tricuspid annular plane systolic excursion were the most significant predictors of Chronic-RVF (receiver operating characteristic–area under the curve = 0.97, 95% confidence interval = 0.91–1.00, according to naïve Bayes). Conclusion: Apical right ventricular strain as well as right atrial strain provides complementary information, both critical to predict acute–right ventricular failure and chronic–right ventricular failure, respectively

    Sunflower and peanut emergency : initial development under sugarcane mulch.

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    The research aimed to evaluate the effect of residual sugarcane mulch on sunflower and peanut plant emergence and initial development. Vases of 4.0 L were disposed in a randomized experimental blocks design, with four replications, in a factorial arrangement of five mulch amounts and three cultivars of each crop. The mulch treatments consisted of four increasing amounts (5, 10, 15 e 20 t ha-1) and a tester with no mulch. The sunflower cultivars were the varieties IAC-iarama and Catissol and the hybrid H-358; the peanut cultivars were IAC-CaiapĂł, Runner 886 and Tatu. The speed emergency index and final percentage, the plant height and shoot dry mass were evaluated. The presence of different levels of sugarcane mulch negatively influences the emergency and initial plant development mainly in peanut but also in sunflower. The negative effects are stronger especially for the runner type of peanut cultivars, while cultivar Tatu was less influenced by the mulch thickness

    Coulomb Dissociation of 27P^{27}P

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    Sic1 plays a role in timing and oscillatory behaviour of B-type cyclins

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    Budding yeast cell cycle oscillates between states of low and high cyclin-dependent kinase activity, driven by association of Cdk1 with B-type (Clb) cyclins. Various Cdk1-Clb complexes are activated and inactivated in a fixed, temporally regulated sequence, inducing the behaviour known as "waves of cyclins". The transition from low to high Clb activity is triggered by degradation of Sic1, the inhibitor of Cdk1-Clb complexes, at the entry to S phase. The G(1) phase is characterized by low Clb activity and high Sic1 levels. High Clb activity and Sic1 proteolysis are found from the beginning of the S phase until the end of mitosis. The mechanism regulating the appearance on schedule of Cdk1-Clb complexes is currently unknown. Here, we analyse oscillations of Clbs, focusing on the role of their inhibitor Sic1. We compare mathematical networks differing in interactions that Sic1 may establish with Cdk1-Clb complexes. Our analysis suggests that the wave-like cyclins pattern derives from the binding of Sic1 to all Clb pairs rather than from Clb degradation. These predictions are experimentally validated, showing that Sic1 indeed interacts and coexists in time with Clbs. Intriguingly, a sic1Delta strain looses cell cycle-regulated periodicity of Clbs, which is observed in the wild type, whether a SIC1-0P strain delays the formation of Clb waves. Our results highlight an additional role for Sic1 in regulating Cdk1-Clb complexes, coordinating their appearance

    Myocardial infarction marker levels are influenced by prothrombin and tumor necrosis factor-\u3b1 gene polymorphisms in young patients.

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    Polymorphisms of genes encoding key factors for the control and activation of inflammatory response and coagulation cascade regulation may play a role in genetic susceptibility to acute myocardial infarction (AMI). This study sought to analyze the effect of TNF - 308G/A and pro-thrombin (FII) 20210G/A polymorphisms on the laboratory parameters of young patients affected by AMI. Results indicated that TNF - 308A positive genotype frequencies were increased in these patients and that a genetically determined higher production of TNF-alpha is associated in young subjects to a more severe cardiac damage as depicted by higher levels of troponin, Creatine kinase-MB Isoenzyme (mCK-MB) and a significant increased plasma fibrinogen levels. Similar and probably additive effects on might have a genetically determined increased production of pro-thrombin even if no significant differences in genotype frequencies of pro-thrombin (FII) 20210G/A polymorphisms were observed in this study. All together these results, indicating the relationship among genetically determined TNF alpha and FII production and increased levels of tissue damage markers of AMI, suggest that a complex genetic background, might be involved in susceptibility to AMI in young men influencing the extension and severity of the disease

    Hypoxia-inducible factor 2α drives nonalcoholic fatty liver progression by triggering hepatocyte release of histidine rich glycoprotein

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    Mechanisms underlying progression of non-alcoholic fatty liver disease (NAFLD) are still incompletely characterized. Hypoxia and hypoxia inducible factors (HIFs) have been implicated in the pathogenesis of chronic liver diseases but the actual role of HIF-2α in the evolution of NAFLD has never been investigated in detail. In this study, we show that HIF-2α is selectively overexpressed in the cytosol and the nuclei of hepatocytes in a very high percentage (> 90%) of liver biopsies from a cohort of NAFLD patients at different stage of the disease evolution. Similar features were also observed in mice with steatohepatitis induced by feeding a methionine/choline-deficient (MCD) diet. Experiments performed in mice carrying hepatocyte-specific deletion of HIF-2α and related control littermates fed with either choline-deficient L-amino acid-refined (CDAA) or MCD diets showed that HIF-2α deletion ameliorated the evolution of NAFLD by decreasing parenchymal injury, fatty liver, lobular inflammation and the development of liver fibrosis. The improvement in NAFLD progression in HIF-2α deficient mice was related to a selective down-regulation in the hepatocyte production of Histidine-Rich Glycoprotein (HRGP), recently proposed to sustain macrophage M1 polarization. In vitro experiments confirmed that the up-regulation of hepatocyte HRGP expression was hypoxia- and HIF-2α-dependent. Finally, analyses performed on specimens from NAFLD patients indicated that HRGP was overexpressed in all patients showing hepatocyte nuclear staining for HIF-2α and revealed a significant positive correlation between HIF-2α and HRGP liver transcripts levels in these patients
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