974 resultados para Symmetry Ratio Algorithm


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Abstract: The VHS and CTR were assessed using computerized thoracic radiographs of ten clinically healthy tufted capuchin monkeys (five males and five females) from the Wild Animal Screening Center in São Luís (Centro de Triagem de Animais Silvestres de São Luís-MA-CETAS). Radiographs were taken in laterolateral and dorsoventral projections to calculate the cardiothoracic ratio (VHS) and vertebral heart size (CTR). The VHS showed mean values of 9.34±0.32v (males) and 9.16±0.34v (females) and there was no statistical difference between males and females (p>0.05). The CTR showed mean values of 0.55±0.04 (males) and 0.52±0.03 (females) and there was no statistical difference between the sexes (p>0.05). There was positive correlation between VHS and CTR (r=0.78). The thoracic and heart diameters showed mean values of 5.70±0.48cm and 2.16±0.40cm in the males, respectively. In the females they measured 5.32±0.39cm and 2.94±0.32cm. There was no statistical difference between the sexes. Our results show that the high correlation found between VHS and CTR permitted the verification with similar clinical precision between the two methods to estimate alterations in the heart silhouette by radiographic examination of tufted capuchin, making it an easy technique to apply that can be considered in the investigation of heart problems for this wild species.

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The determination of the intersection curve between Bézier Surfaces may be seen as the composition of two separated problems: determining initial points and tracing the intersection curve from these points. The Bézier Surface is represented by a parametric function (polynomial with two variables) that maps a point in the tridimensional space from the bidimensional parametric space. In this article, it is proposed an algorithm to determine the initial points of the intersection curve of Bézier Surfaces, based on the solution of polynomial systems with the Projected Polyhedral Method, followed by a method for tracing the intersection curves (Marching Method with differential equations). In order to allow the use of the Projected Polyhedral Method, the equations of the system must be represented in terms of the Bernstein basis, and towards this goal it is proposed a robust and reliable algorithm to exactly transform a multivariable polynomial in terms of power basis to a polynomial written in terms of Bernstein basis .

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In this paper we present an algorithm for the numerical simulation of the cavitation in the hydrodynamic lubrication of journal bearings. Despite the fact that this physical process is usually modelled as a free boundary problem, we adopted the equivalent variational inequality formulation. We propose a two-level iterative algorithm, where the outer iteration is associated to the penalty method, used to transform the variational inequality into a variational equation, and the inner iteration is associated to the conjugate gradient method, used to solve the linear system generated by applying the finite element method to the variational equation. This inner part was implemented using the element by element strategy, which is easily parallelized. We analyse the behavior of two physical parameters and discuss some numerical results. Also, we analyse some results related to the performance of a parallel implementation of the algorithm.

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The superconducting gap is a basic character of a superconductor. While the cuprates and conventional phonon-mediated superconductors are characterized by distinct d- and s-wave pairing symmetries with nodal and nodeless gap distributions respectively, the superconducting gap distributions in iron-based superconductors are rather diversified. While nodeless gap distributions have been directly observed in Ba1–xKxFe2As2, BaFe2–xCoxAs2, LiFeAs, KxFe2–ySe2, and FeTe1–xSex, the signatures of a nodal superconducting gap have been reported in LaOFeP, LiFeP, FeSe, KFe2As2, BaFe2–xRuxAs2, and BaFe2(As1–xPx)2. Due to the multiplicity of the Fermi surface in these compounds s± and d pairing states can be both nodeless and nodal. A nontrivial orbital structure of the order parameter, in particular the presence of the gap nodes, leads to effects in which the disorder is much richer in dx2–y2-wave superconductors than in conventional materials. In contrast to the s-wave case, the Anderson theorem does not work, and nonmagnetic impurities exhibit a strong pair-breaking influence. In addition, a finite concentration of disorder produces a nonzero density of quasiparticle states at zero energy, which results in a considerable modification of the thermodynamic and transport properties at low temperatures. The influence of order parameter symmetry on the vortex core structure in iron-based pnictide and chalcogenide superconductors has been investigated in the framework of quasiclassical Eilenberger equations. The main results of the thesis are as follows. The vortex core characteristics, such as, cutoff parameter, ξh, and core size, ξ2, determined as the distance at which density of the vortex supercurrent reaches its maximum, are calculated in wide temperature, impurity scattering rate, and magnetic field ranges. The cutoff parameter, ξh(B; T; Г), determines the form factor of the flux-line lattice, which can be obtained in _SR, NMR, and SANS experiments. A comparison among the applied pairing symmetries is done. In contrast to s-wave systems, in dx2–y2-wave superconductors, ξh/ξc2 always increases with the scattering rate Г. Field dependence of the cutoff parameter affects strongly on the second moment of the magnetic field distributions, resulting in a significant difference with nonlocal London theory. It is found that normalized ξ2/ξc2(B/Bc2) dependence is increasing with pair-breaking impurity scattering (interband scattering for s±-wave and intraband impurity scattering for d-wave superconductors). Here, ξc2 is the Ginzburg-Landau coherence length determined from the upper critical field Bc2 = Φ0/2πξ2 c2, where Φ0 is a flux quantum. Two types of ξ2/ξc2 magnetic field dependences are obtained for s± superconductors. It has a minimum at low temperatures and small impurity scattering transforming in monotonously decreasing function at strong scattering and high temperatures. The second kind of this dependence has been also found for d-wave superconductors at intermediate and high temperatures. In contrast, impurity scattering results in decreasing of ξ2/ξc2(B/Bc2) dependence in s++ superconductors. A reasonable agreement between calculated ξh/ξc2 values and those obtained experimentally in nonstoichiometric BaFe2–xCoxAs2 (μSR) and stoichiometric LiFeAs (SANS) was found. The values of ξh/ξc2 are much less than one in case of the first compound and much more than one for the other compound. This is explained by different influence of two factors: the value of impurity scattering rate and pairing symmetry.

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This thesis presents a framework for segmentation of clustered overlapping convex objects. The proposed approach is based on a three-step framework in which the tasks of seed point extraction, contour evidence extraction, and contour estimation are addressed. The state-of-art techniques for each step were studied and evaluated using synthetic and real microscopic image data. According to obtained evaluation results, a method combining the best performers in each step was presented. In the proposed method, Fast Radial Symmetry transform, edge-to-marker association algorithm and ellipse fitting are employed for seed point extraction, contour evidence extraction and contour estimation respectively. Using synthetic and real image data, the proposed method was evaluated and compared with two competing methods and the results showed a promising improvement over the competing methods, with high segmentation and size distribution estimation accuracy.

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It has been suggested that the measurement of metronidazole clearance is a sensitive method for evaluating liver function. The aim of this study was to evaluate the usefulness of plasma hydroxy-metronidazole/metronidazole ratios as indicators of dynamic liver function to detect changes resulting from the various forms of chronic hepatitis C virus (HCV) infection. A total of 139 individuals were studied: 14 healthy volunteers, 22 healthy, asymptomatic, consecutive anti-HCV-positive HCV-RNA negative subjects, 81 patients with chronic hepatitis C (49 with moderate/severe chronic hepatitis and 34 with mild hepatitis), and 20 patients with cirrhosis of the liver. HCV status was determined by the polymerase chain reaction. Plasma concentrations of metronidazole and its hydroxy-metabolite were measured by reverse-phase high-performance liquid chromatography with ultraviolet detection in a blood sample collected 10 min after the end of a metronidazole infusion. Anti-HCV-positive HCV-RNA-negative individuals demonstrated a significantly reduced capacity to metabolize intravenously infused metronidazole compared to healthy individuals (0.0478 ± 0.0044 vs 0.0742 ± 0.0232). Liver cirrhosis patients also had a reduced plasma hydroxy-metronidazole/metronidazole ratio when compared to the other groups of anti-HCV-positive individuals (0.0300 ± 0.0032 vs 0.0438 ± 0.0027 (moderate/severe chronic hepatitis) vs 0.0455 ± 0.0026 (mild chronic hepatitis) and vs 0.0478 ± 0.0044 (anti-HCV-positive, HCV-RNA-negative individuals)). These results suggest an impairment of the metronidazole metabolizing system induced by HCV infection that lasts after viral clearance. In those patients with chronic hepatitis C, this impairment is paralleled by progression of the disease to liver cirrhosis.

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The present cross-sectional, population-based study was designed to evaluate the performance of the FEV1/FEV6 ratio for the detection of airway-obstructed subjects compared to the FEV1/FVC <0.70 fixed ratio test, as well as the lower limit of normality (LLN) for 1000 subjects ³40 years of age in the metropolitan area of São Paulo, SP, Brazil. After the exclusion of 37 (3.7%) spirometries, a total of 963 pre-bronchodilator (BD) and 918 post-BD curves were constructed. The majority of the post-BD curves (93.1%) were of very good quality and achieved grade A (762 curves) or B (93 curves). The FEV1/FEV6 and FEV1/FVC ratios were highly correlated (r² = 0.92, P < 0.000). Two receiver operator characteristic curves were constructed in order to express the imbalance between the sensitivity and specificity of the FEV1/FEV6 ratio compared to two FEV1/FVC cut-off points for airway obstruction: equal to 70 (area under the curve = 0.98, P < 0.0001) and the LLN (area under the curve = 0.97, P < 0.0001), in the post-BD curves. According to an FEV1/FVC <0.70, the cut-off point for the FEV1/FEV6 ratio with the highest sum for sensitivity and specificity was 0.75. The FEV1/FEV6 ratio can be considered to be a good alternative to the FEV1/FVC ratio for the diagnosis of airway obstruction, both using a fixed cut-off point or below the LLN as reference. The FEV1/FEV6 ratio has the additional advantage of being an easier maneuver for the subjects and for the lung function technicians, providing a higher reproducibility than traditional spirometry maneuvers.

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Dedikaatio: Johannes Cajanus, Jacobus Frosterus, Laurentius Lithovius, Olaus Lauraeus, Jacobus Falander, Johannes Laibeck, Georgius Aenelius, Johannes Forsman, Abraham Falander, Johannes Argillander.

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We compared the cost-benefit of two algorithms, recently proposed by the Centers for Disease Control and Prevention, USA, with the conventional one, the most appropriate for the diagnosis of hepatitis C virus (HCV) infection in the Brazilian population. Serum samples were obtained from 517 ELISA-positive or -inconclusive blood donors who had returned to Fundação Pró-Sangue/Hemocentro de São Paulo to confirm previous results. Algorithm A was based on signal-to-cut-off (s/co) ratio of ELISA anti-HCV samples that show s/co ratio ³95% concordance with immunoblot (IB) positivity. For algorithm B, reflex nucleic acid amplification testing by PCR was required for ELISA-positive or -inconclusive samples and IB for PCR-negative samples. For algorithm C, all positive or inconclusive ELISA samples were submitted to IB. We observed a similar rate of positive results with the three algorithms: 287, 287, and 285 for A, B, and C, respectively, and 283 were concordant with one another. Indeterminate results from algorithms A and C were elucidated by PCR (expanded algorithm) which detected two more positive samples. The estimated cost of algorithms A and B was US$21,299.39 and US$32,397.40, respectively, which were 43.5 and 14.0% more economic than C (US$37,673.79). The cost can vary according to the technique used. We conclude that both algorithms A and B are suitable for diagnosing HCV infection in the Brazilian population. Furthermore, algorithm A is the more practical and economical one since it requires supplemental tests for only 54% of the samples. Algorithm B provides early information about the presence of viremia.

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Changes in urinary porphyrin excretion may be the result of hereditary causes and/or from environmental or occupational exposure. The objective of this study was to measure the amount of some porphyrins in spot urine samples obtained from volunteers randomly selected from a healthy adult population of São Paulo with a sensitive HPLC method and to estimate normal ranges for a non-exposed population. Spot urine samples were collected from 126 subjects (both genders, 18 to 65 years old) not occupationally exposed to porphyrinogenic agents. Porphyrin fractions were separated on RP-18 HPLC column eluted with a methanol/ammonium acetate buffer gradient, pH 4.0, and measured fluorometrically (excitation 405 nm/emission 620 nm). The amount of porphyrins was corrected for urinary creatinine excretion. Only 8-carboxyl (uro) and 4-carboxyl (copro) porphyrins were quantified as µg/g creatinine. Data regarding age, gender, occupational activities, smoking and drinking habits were analyzed by Mann-Whitney and Kruskal-Wallis tests. Uroporphyrin results did not differ significantly between the subgroups studied. Copro and uro + copro porphyrins were significantly different for smokers (P = 0.008) and occupational activities (P = 0.004). With respect to alcohol consumption, only men drinking >20 g/week showed significant differences in the levels of copro (P = 0.022) and uro + copro porphyrins (P = 0.012). The 2.5-97.5th percentile limit values, excluding those for subjects with an alcohol drinking habit >20 g/week, were 0-20.8, 11.7-93.1, and 15.9-102.9 µg/g creatinine for uro, copro and uro + copro porphyrins, respectively. These percentile limit values can be proposed as a first attempt to provide urinary porphyrin reference values for our population, serving for an early diagnosis of porphyrinopathies or as biomarkers of exposure to porphyrinogenic agents.

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Both genetic background and diet have profound effects on plasma lipid profiles. We hypothesized that a high-carbohydrate (high-CHO) diet may affect the ratios of serum lipids and apolipoproteins (apo) differently in subjects with different genotypes of the SstI polymorphism in the apoCIII gene (APOC3). Fifty-six healthy university students (27 males and 29 females, 22.89 ± 1.80 years) were given a washout diet of 54% carbohydrate for 7 days, followed by a high-CHO diet of 70% carbohydrate for 6 days without total energy restriction. Serum triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apoB100, apoAI, and the APOC3 SstI polymorphism were analyzed. The ratios of serum lipids and apoB100/apoAI were calculated. At baseline, the TG/HDL-C ratio was significantly higher in females, but not in males, with the S2 allele. The differences in the TG/HDL-C ratio between genotypes remained the same after the washout and the high-CHO diet in females. When compared with those before the high-CHO diet, the TC/HDL-C (male S2 carriers: 3.13 ± 1.00 vs 2.36 ± 0.65, P = 0.000; male subjects with the S1S1 genotype: 2.97 ± 0.74 vs 2.09 ± 0.55, P = 0.000; female S2 carriers: 2.68 ± 0.36 vs 2.24 ± 0.37, P = 0.004; female subjects with the S1S1 genotype: 2.69 ± 0.41 vs 2.09 ± 0.31, P = 0.000) and LDL-C/HDL-C (male S2 carriers: 1.44 ± 0.71 vs 1.06 ± 0.26, P = 0.012; male subjects with the S1S1 genotype: 1.35 ± 0.61 vs 1.01 ± 0.29, P = 0.005; female S2 carriers: 1.18 ± 0.33 vs 1.00 ± 0.18, P = 0.049; female subjects with the S1S1 genotype: 1.18 ± 0.35 vs 1.04 ± 0.19, P = 0.026) ratios were significantly decreased after the high-CHO diet regardless of gender and of genotype of the APOC3 SstI polymorphism. However, in female S2 carriers, the TG/HDL-C (1.38 ± 0.46 vs 1.63 ± 0.70, P = 0.039) ratio was significantly increased after the high-CHO diet. In conclusion, the high-CHO diet has favorable effects on the TC/HDL-C and LDL-C/HDL-C ratios regardless of gender and of genotype of the APOC3 SstI polymorphism. Somehow, it enhanced the adverse effect of the S2 allele on the TG/HDL-C ratio only in females.

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In numerous motor tasks, muscles around a joint act coactively to generate opposite torques. A variety of indexes based on electromyography signals have been presented in the literature to quantify muscle coactivation. However, it is not known how to estimate it reliably using such indexes. The goal of this study was to test the reliability of the estimation of muscle coactivation using electromyography. Isometric coactivation was obtained at various muscle activation levels. For this task, any coactivation measurement/index should present the maximal score (100% of coactivation). Two coactivation indexes were applied. In the first, the antagonistic muscle activity (the lower electromyographic signal between two muscles that generate opposite joint torques) is divided by the mean between the agonistic and antagonistic muscle activations. In the second, the ratio between antagonistic and agonistic muscle activation is calculated. Moreover, we computed these indexes considering different electromyographic amplitude normalization procedures. It was found that the first algorithm, with all signals normalized by their respective maximal voluntary coactivation, generates the index closest to the true value (100%), reaching 92 ± 6%. In contrast, the coactivation index value was 82 ± 12% when the second algorithm was applied and the electromyographic signal was not normalized (P < 0.04). The new finding of the present study is that muscle coactivation is more reliably estimated if the EMG signals are normalized by their respective maximal voluntary contraction obtained during maximal coactivation prior to dividing the antagonistic muscle activity by the mean between the agonistic and antagonistic muscle activations.

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The aims of this research were to determine the effect of different conditions of the marination stage on the salt and acid uptake, immersion time, and sensorial characteristics during the marinating process of anchovy (Engraulis anchoita). Different solution:fish ratios and the agitation effect during this stage were analyzed. The ratios used were: 0.77:1, 3:1 and 10:1 (with and without agitation). An increase of marinating solution:fish ratio causes a higher speed of acid and salt penetration The product obtained with the 10:1 ratio had a dry and fibrous texture and a slightly salty taste. Salt concentration was statistically significantly lower (p < 0.01) in the samples with agitation. Agitation did not influence the acid uptake, and the salt penetration speed decreased, but rancidity was detected in this product. The ratio 3:1 decreases the marinating time without damaging sensory attributes and can be used in the fish marinating process.

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The objective of this research was to evaluate the effect of the citric acid concentration, pulp/sugar ratio, and albedo concentration of the passion fruit peel on physical, physiochemical, and sensorial characteristics of the 'Silver' banana preserves. A 2³ factorial design and 3 repetitions in the central point were used. The albedo concentration between 0 and 3% had significant influence on the reduction of the reducing sugars and on the decrease in titratable acidity. The increase in the pulp/sugar ratio exerted a negative effect on the pH and positive on the titratable acidity; the acid addition reduced the non-reducing sugar level. The sensorial evaluation and purchase intention indicated that the incorporation of a maximum of 1.5% albedo in formulations containing 50% pulp and 0.5% citric acid resulted in products with good acceptability in comparison with the formulation in which 60% pulp and an absence of acid or albedo is utilized.

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Rare-earth based upconverting nanoparticles (UCNPs) have attracted much attention due to their unique luminescent properties. The ability to convert multiple photons of lower energy to ones with higher energy through an upconversion (UC) process offers a wide range of applications for UCNPs. The emission intensities and wavelengths of UCNPs are important performance characteristics, which determine the appropriate applications. However, insufficient intensities still limit the use of UCNPs; especially the efficient emission of blue and ultraviolet (UV) light via upconversion remains challenging, as these events require three or more near-infrared (NIR) photons. The aim of the study was to enhance the blue and UV upconversion emission intensities of Tm3+ doped NaYF4 nanoparticles and to demonstrate their utility in in vitro diagnostics. As the distance between the sensitizer and the activator significantly affect the energy transfer efficiency, different strategies were explored to change the local symmetry around the doped lanthanides. One important strategy is the intentional co-doping of active (participate in energy transfer) or passive (do not participate in energy transfer) impurities into the host matrix. The roles of doped passive impurities (K+ and Sc3+) in enhancing the blue and UV upconversions, as well as in influencing the intense UV upconversion emission through excess sensitization (active impurity) were studied. Additionally, the effects of both active and passive impurity doping on the morphological and optical performance of UCNPs were investigated. The applicability of UV emitting UCNPs as an internal light source for glucose sensing in a dry chemistry test strip was demonstrated. The measurements were in agreement with the traditional method based on reflectance measurements using an external UV light source. The use of UCNPs in the glucose test strip offers an alternative detection method with advantages such as control signals for minimizing errors and high penetration of the NIR excitation through the blood sample, which gives more freedom for designing the optical setup. In bioimaging, the excitation of the UCNPs in the transparent IR region of the tissue permits measurements, which are free of background fluorescence and have a high signal-to-background ratio. In addition, the narrow emission bandwidth of the UCNPs enables multiplexed detections. An array-in-well immunoassay was developed using two different UC emission colours. The differentiation between different viral infections and the classification of antibody responses were achieved based on both the position and colour of the signal. The study demonstrates the potential of spectral and spatial multiplexing in the imaging based array-in-well assays.