779 research outputs found

    Effects of the humic acid extracted from vermicompost on the germination and initial growth of Brachiaria brizantha cv. MG5

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    The biological effects of humic substances on vegetables depend on the source of extraction and the concentration used, on the vegetable species and on the age of the plant. This study aimed to evaluate the effect of different humic acid (HA) doses extracted from vermicompost on the germination and initial growth of Brachiaria brizantha cv. MG5. To that end, germination tests were conducted in germination agents, as well as emergence test in greenhouse and seedlings growth test for those agents. For all these tests, five doses of HA [0.0; 1.0; 2.0; 4.0 e 8.0 mM C.L-1] were used, with and without reapplying HA. The following characteristics were analyzed: percentage of germination, percentage of normal seedlings in the first counting of the germination test, percentage of abnormal seedlings, percentage of non-germinated seedlings, percentage of emergence, emergence speed rates, fresh and dry matter of the upper and roots part, length of the upper and roots part and number of lateral roots. Positive effect of HA reapplication in the percentage of abnormal seedlings was observed. With increasing doses of HA, there was a reduction in the percentage of germination and normal seedlings in the first count. The application of HA promoted increase in shoot length and number of lateral root. There was no significant difference in the length of the root. Humus acid affects positively the initial growth of B. brizantha cv. MG5, with the best stimulation being observed when the 2.0 mM C.L-1 dose was applied.Keywords: Forage, Urochloa sp., vigor.Abbreviation: HA, Humic acid

    Improving cluster recovery with feature rescaling factors

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    The data preprocessing stage is crucial in clustering. Features may describe entities using different scales. To rectify this, one usually applies feature normalisation aiming at rescaling features so that none of them overpowers the others in the objective function of the selected clustering algorithm. In this paper, we argue that the rescaling procedure should not treat all features identically. Instead, it should favour the features that are more meaningful for clustering. With this in mind, we introduce a feature rescaling method that takes into account the within-cluster degree of relevance of each feature. Our comprehensive simulation study, carried out on real and synthetic data, with and without noise features, clearly demonstrates that clustering methods that use the proposed data normalization strategy clearly outperform those that use traditional data normalization

    Electromyographic Activity of Masseter and Temporal Muscles with Different Facial Types

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    Objectives: To compare the electromyographic (EMG) activity of the masseter and anterior portion of temporal muscles in different vertical facial types. Materials and Methods: Clinical examination, cephalometric analysis, and electromyographic examination were performed in 44 volunteers ranging from 18 to 35 years old. The volunteers were classified on the basis of their vertical facial characteristics into three groups-brachyfacial, mesofacial, and dolicofacial-by the grouping analysis. The EMG records were obtained with three repetitions during mandibular rest, maximum voluntary contraction in intercuspidation, and simultaneous bilateral isotonic contraction. The Kolmogorov-Smimov and Levene tests were applied to verify the normality and homogeneity of variance. Analysis of variance and the Kruskal-Wallis test identified statistical differences among groups that did not present normality and homogeneity of distribution, respectively. Significance for all statistical tests was set at P <.05. Results: At rest, only the right temporal and masseter muscles presented statistically significant differences among the groups. The differences were observed between groups 1 and 2 (P =.02) and 1 and 3 (P =.038) for the right temporal muscle, and between groups 1 and 2 (P =.029) for the right masseter muscle. Generally, group 1 presented the lowest EMG values for the four muscles evaluated during rest. For isotonic evaluation, none of the groups of muscles presented statistically significant differences. Conclusion: Different vertical facial types do not determine distinct patterns of EMG activity for the masseter and anterior portion of temporal muscles during rest and bilateral mastication. (Angle Orthod. 2009;79:515-520.)79351552

    Semi-automatic algorithm for construction of the left ventricular area variation curve over a complete cardiac cycle

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    <p>Abstract</p> <p>Background</p> <p>Two-dimensional echocardiography (2D-echo) allows the evaluation of cardiac structures and their movements. A wide range of clinical diagnoses are based on the performance of the left ventricle. The evaluation of myocardial function is typically performed by manual segmentation of the ventricular cavity in a series of dynamic images. This process is laborious and operator dependent. The automatic segmentation of the left ventricle in 4-chamber long-axis images during diastole is troublesome, because of the opening of the mitral valve.</p> <p>Methods</p> <p>This work presents a method for segmentation of the left ventricle in dynamic 2D-echo 4-chamber long-axis images over the complete cardiac cycle. The proposed algorithm is based on classic image processing techniques, including time-averaging and wavelet-based denoising, edge enhancement filtering, morphological operations, homotopy modification, and watershed segmentation. The proposed method is semi-automatic, requiring a single user intervention for identification of the position of the mitral valve in the first temporal frame of the video sequence. Image segmentation is performed on a set of dynamic 2D-echo images collected from an examination covering two consecutive cardiac cycles.</p> <p>Results</p> <p>The proposed method is demonstrated and evaluated on twelve healthy volunteers. The results are quantitatively evaluated using four different metrics, in a comparison with contours manually segmented by a specialist, and with four alternative methods from the literature. The method's intra- and inter-operator variabilities are also evaluated.</p> <p>Conclusions</p> <p>The proposed method allows the automatic construction of the area variation curve of the left ventricle corresponding to a complete cardiac cycle. This may potentially be used for the identification of several clinical parameters, including the area variation fraction. This parameter could potentially be used for evaluating the global systolic function of the left ventricle.</p

    Up-regulation of Toll-like receptors 2, 3 and 4 in allergic rhinitis

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    BACKGROUND: Toll-like receptors enable the host to recognize a large number of pathogen-associated molecular patterns such as bacterial lipopolysaccharide, viral RNA, CpG-containing DNA and flagellin. Toll-like receptors have also been shown to play a pivotal role in both innate and adaptive immune responses. The role of Toll-like receptors as a primary part of our microbe defense system has been shown in several studies, but their possible function as mediators in allergy and asthma remains to be established. The present study was designed to examine the expression of Toll-like receptors 2, 3 and 4 in the nasal mucosa of patients with intermittent allergic rhinitis, focusing on changes induced by exposure to pollen. METHODS: 27 healthy controls and 42 patients with seasonal allergic rhinitis volunteered for the study. Nasal biopsies were obtained before and during pollen season as well as before and after allergen challenge. The seasonal material was used for mRNA quantification of Toll-like receptors 2, 3 and 4 with real-time polymerase chain reaction, whereas specimens achieved in conjunction with allergen challenge were used for immunohistochemical localization and quantification of corresponding proteins. RESULTS: mRNA and protein representing Toll-like receptors 2, 3 and 4 could be demonstrated in all specimens. An increase in protein expression for all three receptors could be seen following allergen challenge, whereas a significant increase of mRNA only could be obtained for Toll-like receptor 3 during pollen season. CONCLUSION: The up-regulation of Toll-like receptors 2, 3 and 4 in the nasal mucosa of patients with symptomatic allergic rhinitis supports the idea of a role for Toll-like receptors in allergic airway inflammation

    The elevation in circulating anti-angiogenic factors is independent of markers of neutrophil activation in preeclampsia

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    Background - Severe preeclampsia is associated with increased neutrophil activation and elevated serum soluble endoglin (sEng) and soluble Flt-1 (sFlt-1) in the maternal circulation. To dissect the contribution of systemic inflammation and anti-angiogenic factors in preeclampsia, we investigated the relationships between the circulating markers of neutrophil activation and anti-angiogenic factors in severe preeclampsia or systemic inflammatory state during pregnancy. Methods and results - Serum sEng, sFlt-1, placenta growth factor, interleukin-6 (IL-6), calprotectin, and plasma a-defensins concentrations were measured by ELISA in 88 women of similar gestational age stratified as: severe preeclampsia (sPE, n = 45), maternal systemic inflammatory response (SIR, n = 16) secondary to chorioamnionitis, pyelonephritis or appendicitis; and normotensive controls (CRL, n = 27). Neutrophil activation occurred in sPE and SIR, as a-defensins and calprotectin concentrations were two-fold higher in both groups compared to CRL (P < 0.05 for each). IL-6 concentrations were highest in SIR (P < 0.001), but were higher in sPE than in CRL (P < 0.01). sFlt-1 (P < 0.001) and sEng (P < 0.001) were ˜20-fold higher in sPE compared to CRL, but were not elevated in SIR. In women with sPE, anti-angiogenic factors were not correlated with markers of neutrophil activation (a-defensins, calprotectin) or inflammation (IL-6). Conclusions - Increased systemic inflammation in sPE and SIR does not correlate with increased anti-angiogenic factors, which were specifically elevated in sPE indicating that excessive systemic inflammation is unlikely to be the main contributor to severe preeclampsia
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