1,881 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

    Troponina e infarto periprocedurale: filo di Arianna o folle volo di Icaro?

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    Percutaneous coronary interventions cause frequently an increase in myocardial necrosis markers. Is troponin elevation after percutaneous coronary intervention a predictor of events at follow-up or a consequence of the procedure with no cause-effect relationship with prognosis? The debate is still ope

    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

    Produção de bovinos de corte em manejo intensivo de pastagem.

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    Estacionalidade de produção; Desempenho animal a pasto; Manejo do sistema; Resultados de produção e viabilidade economica.Resumo expandido

    G-protein-coupled receptor kinase 5 polymorphism and Takotsubo cardiomyopathy.

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    BACKGROUND: Takotsubo cardiomyopathy (TTC) is an increasingly reported clinical syndrome that mimics acute myocardial infarction without obstructive coronary artery disease and is characterized by transient systolic dysfunction of the apical and/or mid-segments of the left ventricle. The syndrome mainly occurs in postmenopausal women with high adrenergic state conditions. Nowadays, the pathophysiology of TTC is not yet known and the possibility of a genetic predisposition is controversial. AIMS: The purpose of this study was to assess the genetic susceptibility to TTC through analysis of the L41Q polymorphism of the G-protein-coupled receptor kinase 5 (GRK5). METHODS AND RESULTS: In a cohort of 20 patients enrolled in two tertiary Italian centers with diagnosis of TTC, accordingly to the commonly accepted Mayo Clinic criteria and in 22 healthy individuals (control) we have evaluated the polymorphism in GRK5 gene. The TTC patients had a mean age of 65 ± 9 years and 19 of 20 were women. The presence of one or two L41 alleles of GRK5 was significantly more frequent in TTC group than in the control group (40 vs. 8%, P = 0.0372). CONCLUSION: In our study, we have found a significant difference in the frequency of GRK5 polymorphism between TTC patients and controls, supporting a genetic predisposition to this cardiac syndrome

    Prognostic role of aldosterone in patients with acute coronary syndrome: short and medium term follow-up.

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    AIMS: Different studies have shown a correlation between aldosterone, atherosclerosis and ischemia in the past decade. Evidence exists for the relationship between high levels of aldosterone and augmented risk of cardiovascular diseases, such as hypertension, cardiac failure, coronary artery disease and stroke. The objective of this study was to determine the prognostic role of aldosterone in patients with myocardial infarction. METHODS:The study population included 96 consecutive patients admitted to our department for ST-elevated and non-ST-elevated myocardial infarction from June 2009 to March 2012. Plasma aldosterone levels were measured at admission to hospital in all patients. A 2-year prospective follow-up was performed, and fatal events and non-fatal events, such as reinfarction, congestive heart failure and arrhythmias, were recorded. RESULTS:Aldosterone levels at admission were associated with incidence of congestive heart failure (P\u200a=\u200a0.02), ventricular arrhythmias (P\u200a=\u200a0.01) and all complications (P\u200a=\u200a0.003) after 1-month follow-up. Moreover, high aldosterone levels gave important information in the medium term (24\u200a\ub1\u200a6 months). Specifically, aldosterone was a predictive variable of reinfarction (P\u200a<\u200a0.0001), congestive heart failure (P\u200a<\u200a0.0001) and adverse events (P\u200a=\u200a0.0002). The logistic regression analysis confirmed these results and showed that aldosterone may be predictive of adverse events at medium-term follow-up (odds ratio 1.1, 95% confidence interval 1.03-1.15, P\u200a=\u200a0.02). CONCLUSION:These data show a strong and significant correlation between plasma aldosterone levels at admission for myocardial infarction and fatal and nonfatal adverse events. Aldosterone appears to be a main marker of adverse clinical outcome, in accordance with the literature. These data suggest the need to identify whether antialdosteronic drug treatment, applied acutely in patients with aldosterone elevation, can influence favorably the prognosis of patients with myocardial infarction

    Divergence times and the evolutionary radiation of new world monkeys (Platyrrhini, Primates): an analysis of fossil and molecular data

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    The estimation of phylogenetic relationships and divergence times among a group of organisms is a fundamental first step toward understanding its biological diversification. The time of the most recent or last common ancestor (LCA) of extant platyrrhines is one of the most controversial among scholars of primate evolution. Here we use two molecular based approaches to date the initial divergence of the platyrrhine clade, Bayesian estimations under a relaxed-clock model and substitution rate plus generation time and body size, employing the fossil record and genome datasets. We also explore the robustness of our estimations with respect to changes in topology, fossil constraints and substitution rate, and discuss the implications of our findings for understanding the platyrrhine radiation. Our results suggest that fossil constraints, topology and substitution rate have an important influence on our divergence time estimates. Bayesian estimates using conservative but realistic fossil constraints suggest that the LCA of extant platyrrhines existed at ca. 29 Ma, with the 95% confidence limit for the node ranging from 27-31 Ma. The LCA of extant platyrrhine monkeys based on substitution rate corrected by generation time and body size was established between 21-29 Ma. The estimates based on the two approaches used in this study recalibrate the ages of the major platyrrhine clades and corroborate the hypothesis that they constitute very old lineages. These results can help reconcile several controversial points concerning the affinities of key early Miocene fossils that have arisen among paleontologists and molecular systematists. However, they cannot resolve the controversy of whether these fossil species truly belong to the extant lineages or to a stem platyrrhine clade. That question can only be resolved by morphology. Finally, we show that the use of different approaches and well supported fossil information gives a more robust divergence time estimate of a clade.Facultad de Ciencias Naturales y Muse

    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
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