952 resultados para Two photon absorption and nonlinear
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This study investigated the psychometric properties of the Horizontal and Vertical Individualism and Collectivism Scale (HVIC) and the Auckland Individualism and Collectivism Scale (AICS). The sample consisted of 1,403 working individuals from Switzerland (N = 585) and from South Africa (N = 818). Principal component factor analyses indicated that a two-factor structure replicated well across the two countries for both scales. In addition, the HVIC four-factor structure replicated well across countries, whereas the responsibility dimension of individualism of the AICS replicated poorly. Confirmatory factor analyses provided satisfactory support to the original theoretical models for both the HVIC and the AICS. Equivalence measurement indices indicated that the cross-cultural replicability properties of both instruments are generally acceptable. However, canonical correlations and correlations between the HVIC and AICS dimensions confirm that these two instruments differ in their underlying meaning of the individualism and collectivism constructs, suggesting that these two instruments assess individualism and collectivism differently.
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The coupling between topography, waves and currents in the surf zone may selforganize to produce the formation of shore-transverse or shore-oblique sand bars on an otherwise alongshore uniform beach. In the absence of shore-parallel bars, this has been shown by previous studies of linear stability analysis, but is now extended to the finite-amplitude regime. To this end, a nonlinear model coupling wave transformation and breaking, a shallow-water equations solver, sediment transport and bed updating is developed. The sediment flux consists of a stirring factor multiplied by the depthaveraged current plus a downslope correction. It is found that the cross-shore profile of the ratio of stirring factor to water depth together with the wave incidence angle primarily determine the shape and the type of bars, either transverse or oblique to the shore. In the latter case, they can open an acute angle against the current (upcurrent oriented) or with the current (down-current oriented). At the initial stages of development, both the intensity of the instability which is responsible for the formation of the bars and the damping due to downslope transport grow at a similar rate with bar amplitude, the former being somewhat stronger. As bars keep on growing, their finite-amplitude shape either enhances downslope transport or weakens the instability mechanism so that an equilibrium between both opposing tendencies occurs, leading to a final saturated amplitude. The overall shape of the saturated bars in plan view is similar to that of the small-amplitude ones. However, the final spacings may be up to a factor of 2 larger and final celerities can also be about a factor of 2 smaller or larger. In the case of alongshore migrating bars, the asymmetry of the longshore sections, the lee being steeper than the stoss, is well reproduced. Complex dynamics with merging and splitting of individual bars sometimes occur. Finally, in the case of shore-normal incidence the rip currents in the troughs between the bars are jet-like while the onshore return flow is wider and weaker as is observed in nature.
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In this paper we will find a continuous of periodic orbits passing near infinity for a class of polynomial vector fields in R3. We consider polynomial vector fields that are invariant under a symmetry with respect to a plane and that possess a “generalized heteroclinic loop” formed by two singular points e+ and e− at infinity and their invariant manifolds � and . � is an invariant manifold of dimension 1 formed by an orbit going from e− to e+, � is contained in R3 and is transversal to . is an invariant manifold of dimension 2 at infinity. In fact, is the 2–dimensional sphere at infinity in the Poincar´e compactification minus the singular points e+ and e−. The main tool for proving the existence of such periodic orbits is the construction of a Poincar´e map along the generalized heteroclinic loop together with the symmetry with respect to .
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In this paper we consider vector fields in R3 that are invariant under a suitable symmetry and that posses a “generalized heteroclinic loop” L formed by two singular points (e+ and e −) and their invariant manifolds: one of dimension 2 (a sphere minus the points e+ and e −) and one of dimension 1 (the open diameter of the sphere having endpoints e+ and e −). In particular, we analyze the dynamics of the vector field near the heteroclinic loop L by means of a convenient Poincar´e map, and we prove the existence of infinitely many symmetric periodic orbits near L. We also study two families of vector fields satisfying this dynamics. The first one is a class of quadratic polynomial vector fields in R3, and the second one is the charged rhomboidal four body problem.
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In this paper, an advanced technique for the generation of deformation maps using synthetic aperture radar (SAR) data is presented. The algorithm estimates the linear and nonlinear components of the displacement, the error of the digital elevation model (DEM) used to cancel the topographic terms, and the atmospheric artifacts from a reduced set of low spatial resolution interferograms. The pixel candidates are selected from those presenting a good coherence level in the whole set of interferograms and the resulting nonuniform mesh tessellated with the Delauney triangulation to establish connections among them. The linear component of movement and DEM error are estimated adjusting a linear model to the data only on the connections. Later on, this information, once unwrapped to retrieve the absolute values, is used to calculate the nonlinear component of movement and atmospheric artifacts with alternate filtering techniques in both the temporal and spatial domains. The method presents high flexibility with respect to the required number of images and the baselines length. However, better results are obtained with large datasets of short baseline interferograms. The technique has been tested with European Remote Sensing SAR data from an area of Catalonia (Spain) and validated with on-field precise leveling measurements.
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One of the most important problems in optical pattern recognition by correlation is the appearance of sidelobes in the correlation plane, which causes false alarms. We present a method that eliminate sidelobes of up to a given height if certain conditions are satisfied. The method can be applied to any generalized synthetic discriminant function filter and is capable of rejecting lateral peaks that are even higher than the central correlation. Satisfactory results were obtained in both computer simulations and optical implementation.
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The prevalence of obesity and type 2 diabetes has increased at an alarming rate in developed countries. It seems in the light of current knowledge that metabolic syndrome may not develop at all without NAFLD, and NAFLD is estimated to be as common as metabolic syndrome in western population (23 % occurrence). Fat in the liver is called ectopic fat, which is triacylglycerols within the cells of non-adipose tissue. Serum alanine aminotransferase (ALT) values correlate positively with liver fat proportions, and increased activity of ALT predicts type 2 diabetes independently from obesity. Berries, high in natural bioactive compounds, have indicated the potential to reduce the risk of obesity-related diseases. Ectopic fat induces common endocrine excretion of adipose tissue resulting in the overproduction of inflammatory markers, which further induce insulin resistance by multiple mechanisms. Insulin resistance inducing hyperinsulinemia and lipolysis in adipocytes increases the concentration of free fatty acids and consequently causes further fat accumulation in hepatocytes. Polyphenolic fractions of berries have been shown to reverse inflammatory reaction cascades in in vitro and animal studies, and moreover to decrease ectopic fat accumulation. The aim of this thesis was to explore the role of northern berries in obesity-related diseases. The absorption and metabolism of selected berry polyphenols, flavonol glycosides and anthocyanins, was investigated in humans, and metabolites of the studied compounds were identified in plasma and urine samples (I, II). Further, the effects of berries on the risk factors of metabolic syndrome were studied in clinical intervention trials (III, IV), and the different fractions of sea buckthorn berry were tested for their ability to reduce postprandial glycemia and insulinemia after high-glucose meal in a postprandial study with humans (V). The marked impact of mixed berries on plasma ALT values (III), as well as indications of the positive effects of sea buckthorn, its fractions and bilberry on omental adiposity and adhesion molecules (IV) were observed. In study V, sea buckthorn and its polyphenol fractions had a promising effect on potprandial metabolism after high-glucose meal. In the literature review, the possible mechanisms behind the observed effects have been discussed with a special emphasis on ectopic fat accumulation. The literature review indicated that especially tannins and flavonoids have shown potential in suppressing diverse reaction cascades related to systemic inflammation, ectopic fat accumulation and insulin resistance development.
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This study was carried out to determine some physiological and phenological responses of the bean under high [CO2] and drought stress. The experiment was conducted from April to July 2009 in Viçosa, Brazil. The open-top chambers were used to enrich the air with CO2, whereas the drought stress was applied between the flowering and the ripening. The randomized block design was used, with four replicates in the subplots. The following plots were [CO2] at 700ppm (F1) and [CO2] environmental (F2) and the subplots were well watering (S1) and drought stress (S2). The results were subjected to Anova and the Tukey test (P < 0.05). For the treatments F1S1 and F1S2 the photosynthetic rate showed increments of 59% and the transpiration reduction of 12%. The yield, leaf temperature and stomatal conductance were not significant different to high [CO2], different from the dry matter, who showed increment of 20% (F1S1) and the water use efficiency who showed increase of 90% for high [CO2]. The osmotic potential was lower in plants under drought stress (F2S2 and F1S2), followed by plants under high [CO2] (F1S1). Despite the increment in photosynthesis, high [CO2] does not guarantee higher yield.
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The ocelot (Leopardus pardalis) is included in list of wild felid species protected by CITES and is part of conservation strategies that necessarily involve the use of assisted reproduction techniques, which requires practical and minimally invasive techniques of high reproducibility that permit the study of animal reproductive physiology. The objective of this study was to compare and validate two commercial assays: ImmuChem Double Antibody Corticosterone 125I RIA from ICN Biomedicals, Costa Mesa, CA, USA; and Coat-a-Count Cortisol 125I RIA from DPC, Los Angeles, CA, USA, for assessment of fecal glucocorticoid metabolites in ocelots submitted to ACTH (adrenocorticotropic hormone) challenge. Fecal samples were collected from five ocelots kept at the Brazilian Center of Neotropical Felines, Associação Mata Ciliar, São Paulo, Brazil, and one of the animals was chosen as a negative control. The experiment was conducted over a period of 9 days. On day 0, a total dose of 100 IU ACTH was administered intramuscularly. Immediately after collection the samples were stored at 20C in labeled plastic bags. The hormone metabolites were subsequently extracted and assayed using the two commercial kits. Previously it was performed a trial with the DPC kit to check the best extraction method for hormones metabolites. Data were analyzed with the SAS program for Windows V8 and reported as means ± SEM. The Schwarzenberger extraction method was slightly better when compared with the Wasser extraction method (103,334.56 ± 19,010.37ng/g of wet feces and 59,223.61 ± 12,725.36ng/g of wet feces respectively; P=0,0657). The ICN kit detected an increase in glucocorticoid metabolite concentrations in a more reliable manner. Metabolite concentrations (ng/g wet feces) on day 0 and day 1 were 66,956.28 ± 36,786.93 and 92,991.19 ± 28,555.63 for the DPC kit, and 205,483.32 ± 83,811.32 and 814,578.75 ± 292,150.47 for the ICN kit, respectively. The limit of detection for the ICN kit was 7.7 ng/mL for 100% B/Bo (25ng/mL for 88%B/Bo) and for the DPC kit it was 0.2ug/dL for 90.95% B/Bo (1ug/dL for 81.27% B/Bo). In conclusion it was confirmed that the Schwarzenberger extraction method and the ICN kit are superior for extracting and measuring fecal glucocorticoid metabolites in ocelot fecal samples.
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The objectives of this study were to evaluate and compare the use of linear and nonlinear methods for analysis of heart rate variability (HRV) in healthy subjects and in patients after acute myocardial infarction (AMI). Heart rate (HR) was recorded for 15 min in the supine position in 10 patients with AMI taking β-blockers (aged 57 ± 9 years) and in 11 healthy subjects (aged 53 ± 4 years). HRV was analyzed in the time domain (RMSSD and RMSM), the frequency domain using low- and high-frequency bands in normalized units (nu; LFnu and HFnu) and the LF/HF ratio and approximate entropy (ApEn) were determined. There was a correlation (P < 0.05) of RMSSD, RMSM, LFnu, HFnu, and the LF/HF ratio index with the ApEn of the AMI group on the 2nd (r = 0.87, 0.65, 0.72, 0.72, and 0.64) and 7th day (r = 0.88, 0.70, 0.69, 0.69, and 0.87) and of the healthy group (r = 0.63, 0.71, 0.63, 0.63, and 0.74), respectively. The median HRV indexes of the AMI group on the 2nd and 7th day differed from the healthy group (P < 0.05): RMSSD = 10.37, 19.95, 24.81; RMSM = 23.47, 31.96, 43.79; LFnu = 0.79, 0.79, 0.62; HFnu = 0.20, 0.20, 0.37; LF/HF ratio = 3.87, 3.94, 1.65; ApEn = 1.01, 1.24, 1.31, respectively. There was agreement between the methods, suggesting that these have the same power to evaluate autonomic modulation of HR in both AMI patients and healthy subjects. AMI contributed to a reduction in cardiac signal irregularity, higher sympathetic modulation and lower vagal modulation.
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Pro Gradu -tutkielmassani tarkastelen Ernest Hemingwayn alun perin vuonna 1925 julkaistuja kahta novellia ”Big Two-Hearted River” ja ”Indian Camp”. Molemmat teokset kuuluvat Nick Adams -tarinoihin, jotka ovat kokoelma novelleja, joissa Hemingway kuvaa Nick Adamsin elämää pojasta mieheksi. Nick Adams on usein tulkittu Hemingwayn alter egoksi ja monet tapahtumat ovatkin suoraa heijastusta Hemingwayn elämästä. Päähenkilön lisäksi monia Nick Adams -tarinoita yhdistää luonnon vahva läsnäolo ja Hemingwayn kuuluisan maalauksellinen miljöön deskriptiivisyys. Käyttämäni ekokriittisen teorian avulla pyrin osoittamaan tutkielmassani, että Nick Adamsin hahmo peilautuu miljöökuvauksessa syventyen dynaamiseksi hahmoksi ja että Hemingwayn luonto- ja ympäristökuvaus peilaa hahmon sisäistä maailmaa hyvinkin läheisesti. Tutkimukseni teoreettinen viitekehys, ekokritiikki, on kirjallisuudentutkimuksen suuntaus, joka tutkii ihmisen ja fyysisen ympäristön suhdetta toisiinsa. Lisäksi hyödynnän tutkielmassani dikotomioita, joiden avulla tarkastelen ja analysoin novelleista nousevia aiheita. Esimerkiksi seuraavat dikotomiat ovat keskeisiä molemmissa novelleissa: kulttuuri vs. luonto, pastoraali vs. erämaa, matka vs. oleskelu, keho vs. mieli, vesi vs. maa, tuli tai valo vs. vesi ja elämä vs. kuolema.
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Presence of surface glycoprotein in Piptocephalis virginiana that recognizes the host glycoproteins band c, reported earlier from our laboratory, was detected by immunofluorescence microscopy. Germinated spores of P. virginiana treated with Mortierella pusilla cell wall protein extract, primary antibodies prepared against glycoproteins band c and FITC-goat anti-rabbit IgG conjugate showed fluorescence. This indicated that on the surfaces of the biotrophic mycoparasite P. virginiana , there might be a complementary molecule which recognizes the glycoproteins band c from M. pusilla. Immunobinding analysis identified a glycoprotein of Mr 100 kDa from the mycoparasite which binds with the host glycoproteins band c, separately as well as collectively. Purification of this glycoprotein was achieved by (i) 60% ammonium sulfate precipitation, (ii) followed by heat treatment, and (iii) Sephadex G-IOO gel filtration. The glycoprotein was isolated by preparative polyacrylamide gel electrophoresis by cutting and elution. The purity of the protein ·was ascertained by SDS-PAGE and Western blot analysis. Positive reaction to periodic acid-Schiff reagent revealed the glycoprotein nature of this 100 kDa protein. Mannose was identified as a major sugar component of this glycoprotein by using a BoehringerMannheim Glycan Differentiation Kit. Electrophoretically purified glycoprotein was used to raIse polyclonal antibody in rabbit. The specificity of the antibody was determined by dot-immunobinding test and western-blot analysis. Immunofluorescence mIcroscopy revealed surface localization of the protein on the germ tube of Piptocephalis virginiana. Fluorescence was also observed at the surfaceJ of the germinated spores and hyphae of the host, M. pusilla after treatment with complementary protein from P. virginiana, primary antibody prepared against the complementary protein and FITC-goat anti-rabbit IgG conjugate.